- 4 days ago
This video you will learn the
1. What is shell & tube heat exchanger
2. Part of S&T Exchanger
3. TEMA type
4. Selection Guideline for Shell & tube exchanger
1. What is shell & tube heat exchanger
2. Part of S&T Exchanger
3. TEMA type
4. Selection Guideline for Shell & tube exchanger
Category
📚
LearningTranscript
00:01Hi friends, welcome to our channel concept engineering flux focus on fundamentals.
00:06We have started lecture on model 2 heat exchangers.
00:11In today's session we will continue on introduction to heat exchanger part 2 shell and tube exchangers.
00:19In this session we will learn part of shell and tube heat exchanger,
00:23what are the different parts of shell and tube heat exchanger,
00:26what is the tema nomenclature for shell and tube exchangers,
00:28what are the different parts and selection guideline for shell and tube heat exchangers.
00:35So, let us start with the important parts of the shell and tube heat exchanger.
00:41So, this is a complete shell and tube heat exchanger.
00:44So, first important part is the shell.
00:46This is the large outer container that enclose the tubes and one this is the complete is called the shell
00:54covering everything
00:55and one side fluid flows through the shell side.
01:00Tube bundle is the whole bundles, you can say that it is a tube bundle and it consists of tubes,
01:10what are the number of tubes based on the selection and the second fluid flows through this tube bundle.
01:15It can be tube bundle can have a different passes and this is the main surface of this tubes will
01:25be the heat transfer takes place.
01:29Then tube sheet, this part is called as tube sheet.
01:32If you see in this picture, this is the tube sheet.
01:35This is a very important part, this separates your shell side fluid and tube side fluid from the mixing.
01:42So, that is the important part of the heat exchanger.
01:46This is like a circular metal plate, holes for the tubes will be there and it gives,
01:52this is also telling you the what are the different passes on the tube sides.
01:57It also shows.
02:00Then this is the tube side connection inlet.
02:04Baffles are also the important part of the heat exchanger.
02:10It supports the tubes and it supports in preventing the vibration as well and it will give the flow part
02:22to the shell side fluid.
02:23So, shell side fluid will move based on how the baffles are placed.
02:29Baffles can be placed vertical, baffles can be placed horizontal based on the fluid selection it is depending on.
02:37Then this is the front channel.
02:39This complete section is called front channel.
02:41We will see how different type of front channels are available.
02:43And then this is the rear channel which is also the important part.
02:47So, combined of this shell, front end and rear end will give the complete exchanger.
02:52So, all the heat exchangers happen within that.
02:56And then one more part is expansion joint.
02:58Basically, expansion joint comes in the fixed tube heat exchangers.
03:04So, we will see in detail how the expansion joint is important.
03:08Expansion below or expansion joint in a fixed tube heat exchanger where the tubes or tube sheet is fixed on
03:15the both end of the shell.
03:17And if the fluid in the tube is hotter.
03:22So, if the tube is hotter, then the tube expansion expansion means it can expand on any side.
03:30The rate of expansion of the tubes can be different.
03:33So, if suppose the tube is expanding maybe 5 mm or 6 mm.
03:40Just suppose in a number, random number.
03:42And the shell side fluid is colder and it expands just like a 2 mm or 1 mm only on
03:50both side.
03:511 mm or 2 mm.
03:52So, the difference because of this 3 mm difference is there.
03:56So, the shell will get stressed because the tube sheets are fixed on the both end of the shell.
04:04So, tubes are trying to expand.
04:06So, either tube can get break or shell can whichever based on the thickness or the tube thickness is less
04:13than tube can also get damaged because it wants to expand.
04:16But however, the shell is not allowing it to expand.
04:19So, in that case, this type of bellows are provided or you can say bellows expansion bellows or expansion joints
04:25are providing which allows the shell to expand on expand with the tubes.
04:32So, it will even the temperature on the shell side is lower still shell can be expand.
04:38So, this will help you in damaging your exchanger either on the tube side or shell side.
04:42So, that is why expansion joint is very much important for the fixed tube heat exchanger.
04:49So, in this cross sectional we will see the two important part of the shell and tube heat exchanger.
04:53First is the impeachment plate.
04:55Impeachment plate basically its position just below the shell inlet.
04:59This is the shell inlet and it is positioned just below to the shell inlet on the tubes.
05:05So, it will help to protect the top most tube from the high velocity which is coming from the shell
05:11side pipes.
05:13So, when the shell side fluid enters it will have a high velocity and that high velocity directly hit on
05:18the tube.
05:19So, it protects that high momentum of the fluid entering from the shell without it direct blast of the fluid
05:26can happen and it may damage or cause the erosion or vibration damages to this tube.
05:33So, that is why this impeachment plate is very important.
05:37Similarly, the second important part is tie rods and spacer.
05:42Tie rods are like the thin rods.
05:44These are the thin rods which passes through the baffle holes and the tube sheet and it is connecting with
05:52the tube sheets holding them and providing the structure rigidity.
05:57Because without this, the baffles may not remain at that place.
06:04Because of the shell side fluid force it may move here and there or it may tilt it or displace
06:10from its original place.
06:12So, this tie rods and spacer helps it to keep it at the place.
06:16And basically spacer is the short tubes or pipes between the rods or adjacent baffles.
06:25So, between these two adjacent baffles there is a spacer they are given to keep this distance proper completely all
06:32the time.
06:33So, this is basically correct the spacing of the baffles and it is maintained throughout its lifetime.
06:43In this first picture you are seeing the pass partition plate.
06:47This is basically this part partition plates are installed in the channel cover on the front header or this is
06:54on the front side and this can be on the rear end.
06:57So, this will give the number of passes like this every time this is the inlet suppose on the tube
07:03side.
07:04So, fluid goes from this inside and when it goes at this end it will just transfer from this side.
07:09So, it is giving the number of passes.
07:12So, part partition plates are for the providing the passes and if you see this is a tube sheet.
07:19This is a tube sheet where the tubes are inserted without welding now tubes before the welding on the tube
07:26sheets.
07:26And when it is welded it looks like this.
07:29So, this is a complete tube sheet.
07:33Some places expansion joint just provided at the one side of the exchanger.
07:38It can be in the middle depending on the design.
07:42And this third picture is the your floating head, floating head exchanger.
07:49So, in this your tube sheet is getting float with the end cover basically.
07:55So, that is why it will help in expansion.
07:59It does not need in floating head it does not need the expansion bellows.
08:06So, that is the alternate.
08:07But however, the cost is important cost of bellow versus the cost of floating head that decides your priority.
08:16Basically, TEMA provides the standard terminology and nomenclature for the shell and tube heat exchanger.
08:21This is a fixed tube heat exchanger BEM.
08:24For this basically TEMA provides the nomenclature around 40 nomenclature.
08:29So, you can see the number and on this figure and there are 20 on this page.
08:35So, this is a fixed tube.
08:36You can just go one by one and you can able to see the which are the different nomenclature used
08:40by the TEMA.
08:42So, this is on the floating head AES.
08:45You can see the different again the same total 39 nomenclature are there.
08:52So, you can see one by one on this number.
08:54So, I am not explaining this because this is not just pictorial orientation for this.
08:59Everything is mentioned with the number.
09:01So, you can just check it.
09:04There are some limitations to shell and tube heat exchangers.
09:08The limitations are first limitation is the diameter.
09:11The diameter of shell and tube heat exchanger shall not be more than 100 inches or you can say 2
09:17.45 meter.
09:19This is not a TEMA guideline but generally this is followed because when you increase the diameter,
09:25your tube side fabrication will be difficult because your tube sheet main part is a tube sheet.
09:30So, tube sheet when you for this high diameter, the number of thousands holes maybe you have to drill.
09:37The accuracy of that may not be possible and that is why it is avoided that to go for the
09:44higher diameter.
09:45Also, the flange rating and the flange when you go for a higher diameter of 2.4 meter then the
09:52number of bolts and other things will be very high.
09:56So, accuracy getting accuracy will be difficult.
09:59Also, all these exchangers are manufactured in the fabrication shop.
10:05So, lifting and transferring is also an issue.
10:08So, that is why these diameters are limited to 100 inches or you can say 2.45 meter.
10:19Similarly, the other limitation is the design pressure.
10:23The design pressure basically limited for the tube sheet design basically.
10:28Once we are going for the higher pressure as we know, the tube sheet is only the part which is
10:35separating your shell and tube.
10:36So, the thickness of the tube sheet will be higher when you go for the higher pressure.
10:41It is not like that you cannot go more than 3000 psi in heat exchanger.
10:46You can go but the manufacturing will be very difficult in that case.
10:51And the special is instead of that if you can go for a smaller exchanger or different type of exchangers
10:58will be the better.
10:59So, that is why this 3000 psi limit is given.
11:05And there is one more check point for all the engineers to just to check that your design pressure and
11:13your nominal diameter of the exchanger if it should not exceed the value of 1 lakh.
11:22So, this is a simple you can say checkpoint for the engineers because when you in that case you can
11:29find out that if these values are exceeding then your manufacturing is very difficult.
11:33So, suppose if you are if you have a exchanger with a very high pressure.
11:39So, suppose you have exchanger you want at 5000 psi.
11:43So, what you have to do just check that divide 1 lakh divided by 5000 it comes around 5000 it
11:54comes around 20.
11:55So, your diameter of your exchanger should not increase the 20 inches that is a limitation if you are going
12:02for a higher psi pressure.
12:05Similarly, if you are going for a very high diameter exchanger suppose then you can just check that 1 lakh
12:11divided by you can say 100 mm sorry 100 inches.
12:17So, in that case you will find that your pressure should not increase if you just 100 divided by this
12:24so your pressure should not increase by 1000 psi it will be only the 1000 psi.
12:30So, this is the check point the multiplication of your diameter and the design pressure will give you the limiting
12:38factor for this.
12:40So, basically all these limitations you can say or you can say why we follow this because the intent is
12:49only to limiting the wall thickness maximum wall thickness approximately to the 3 inches.
12:54It should not increase more than 3 inches and the maximum stud diameter to the 4 inches because if the
13:00thickness increases more than 3 inches if it is increased on the tube side.
13:05So, definitely tube side thickness increases then your heat exchange will be lower.
13:09So, that is why these limitations or you can say it is given.
13:14However, this is not a TEMA limitation this is a general guideline which is followed by worldwide to limiting the
13:21exchanger design.
13:23Instead of that in such cases we can go over for the multiple exchangers if you find the difficulties in
13:30getting this type of exchangers.
13:34So, component of exchanger I think this picture has seen by everybody that these are the front end shell type
13:40and rear type.
13:42This is available in all books.
13:43So, we will just see we will not go through the detail in this picture.
13:47We will just see what are the A, B, C, D the front end is used how this E, F,
13:53G, H, J, K, X is used.
13:56And how the rear end is what is the important of it and when it is used.
14:02The front head design.
14:03So, first is the A type.
14:05Basically A type is easy to open for the tube side excess and extra tube side joint.
14:10So, basically if you see this A why it is say that easy to open because the pipeline you can
14:15say when you are putting exchanger you there will be this is the pipeline.
14:18So, this A type front end can be removed without removing without dismantling this inlet pipelines that is why it
14:24is easy to open.
14:26However, it will give you the extra joint which main leaks because here already then one joint for the your
14:34front end and this is an additional joints.
14:37So, this is a limitations for this.
14:39So, we have to see if your service is very fouling and you frequently want to check on the tube
14:45side any fouling or anything is there.
14:47Then this A type can be used.
14:51The second is B type.
14:52B type is must break piping because as I said in A there is no requirement of piping but this
14:58B type front end when you have to remove.
15:01You have to remove your piping from here.
15:03So, you have to maybe put some removable spool here and then you can move the piping.
15:12And single tube side joint.
15:13So, this is giving you a single tube side joint that is advantage of it.
15:17So, it is depending on which type of you can select.
15:21We will see what are the criteria we have to see A, B, M.
15:25But B is also preferable one because it is giving a one side.
15:30When it is a fixed tube sheets you can generally go for B, E, M.
15:34So, B is also preferable one front end.
15:38Third is a C type.
15:40This is a channel tube shell joint eliminates.
15:43Actually, this in this type basically the channel tube joint is eliminated means the tube sheet is fixed with the
15:50front end itself.
15:51And the opening is on this only the plate you have to remove.
15:57So, here also you no need to remove your piping as well if you just want to inspect on the
16:02tube side.
16:03So, that is why it is called bundle integrated with the front end.
16:06So, this bundle is already integrated with the front end.
16:09Then end type.
16:11This is a fixed tube sheet with a removable cover.
16:14So, it is a A, C.
16:16This is a tube sheet is fixed here and with a removable cover.
16:20Fixed tube sheet with the removable cover.
16:24This cover can be removed but this completely fixed with the front end similar to the C types basically.
16:37D type is this is a special closure and high pressure application where the 4000 psi as we said the
16:43maximum we can go up to 5000 psi.
16:46You can go 3000 psi basically but if you are going for a very high pressure you can go for
16:51this front end where the additional this type of arrangement is given.
16:56This is called a D type and this is here also the tube sheet is fixed with your front end.
17:03The difference between the C and N is only that in this you can remove your tube sheets basically because
17:09there is an additional flange here which is connecting to the shell.
17:12So, your tube sheet can be removed with this part of the front end.
17:17However, in N type you cannot remove.
17:19It is a fixed tube.
17:20So, the tubes cannot come out.
17:22It is a fixed.
17:26The shell types in shell and tube reduction your first type is E.
17:30E is used very commonly when the configuration where you do not have any phase change.
17:34So, when you have like a preheater or anything there you can use or where there is a no phase
17:40change to liquid to liquid exchange or to gas to liquid.
17:42You can use it.
17:44Generally, the shell side flow path is similar to little bit cross type of flow path and this can be
17:51used for the fixed tube as well.
17:55This E type generally BEM and other things is used for the fixed tube.
18:01Then F is the counter current flow obtained with this F.
18:08So, flow on the shell side it goes like this and comes in this way.
18:11So, if you have the inlet from this side the tube side goes in this way and the second pass
18:16is go.
18:17So, you will get the counter exact counter current flow on the tube side sorry on the shell side.
18:24Otherwise, sometimes it is a cross flow as well.
18:27When you required a very low delta P or a lower delta P on the shell side then you can
18:32go for the G type.
18:33And the flow basically goes as a split flow from the both end there is a partition plate in between.
18:40So, flow will be divided in the shell pass.
18:44H type is generally used for the thermosyphon reboiler.
18:48Thermosyphon reboiler is a separate topic.
18:50We will do one session on thermosyphon reboiler how to design it because it is having some typical requirements.
18:57However, the exercise is like a two partition plate and flow is divided in the shell for the two times.
19:04So, you can say it is divided in two times here divided flow two shell passes for each section.
19:10J type is like these are the old reboiler designs.
19:14So, you can say before cattle it can be used like reboiler.
19:18So, liquid comes from the bottom and vapor can be taken from the top.
19:25When there is a requirement of phase change then you can use a cattle type reboiler.
19:30So, wherever you like in a steam reboiler or any reboilers for the columns or any vaporizer you can use
19:37a cattle type.
19:38So, where the liquid can enter from the bottom it will get a vapor forms and the tubes will be
19:43always filled with the liquid if you want.
19:45And then there will be a baffle to overflow the liquid.
19:48So, liquid the tubes remain submerged in this and there is a lot of vapor space available.
19:53So, generally K type use when you have a phase change.
19:59X type is when you need a lowest delta then you can go for the X type.
20:03So, in this basically there may be chances of cross you can say cross circuit and flow can be shell
20:10side flow can be directly go out.
20:13So, maybe little bit less preferable less heat exchange in this type of shell.
20:19So, rear end of the shell and tube heat exchangers the L type basically L type is similar to the
20:25A type of the front end.
20:28So, where you can see the tube sheet is attached here and you can remove this end cover and you
20:33can see the tubes from the rear end as well.
20:37M type is also similar to the B type of the heat exchanger sorry front end.
20:44So, where you need to remove the complete rear end to see the tubes from the rear end and here
20:51you have to dismantle the piping as well in this you may not need to remove the piping.
20:57End type is also same as the end type of the front end.
21:01So, where you can remove this end cover and tube sheet is attached here.
21:06So, this is similar to the end type and P and W type generally not used normally in refinery.
21:13So, it is also the one type of rear end where you can see the tube sheet is attached and
21:18the end cover is available here.
21:20In this W is also little it is it is a floating sheet which is attached to the end cover.
21:27Here you can see the end cover can be removed but generally these remains are the tube to pass and
21:36generally this is not used.
21:38So, that was it was not basically discussed.
21:43The important rear end is S type and the T type basically we will see both together.
21:48So, basically S type is the floating head with the blocking ring.
21:53So, this is the ring basically which this part you are seeing this is the ring.
21:57So, this is differentiate between the two S and T type and the T type is having the floating head
22:03with pull through the shell.
22:05So, in this there is no this is the shell part.
22:09This is the shell part and this is the pull through you can say the tube sheet can be pulled
22:16out from here.
22:18But here there is a ring in the S type.
22:22So, basically these two are used in when there is a floating type heat exchanger.
22:30So, basically this is more difficult because there is a ring.
22:34So, when you have to remove this tube bundle you have to open the rear end and then you have
22:40to remove this ring and then only you can pull the bundle.
22:43But however in the T type you can pull the bundle directly from the front end.
22:49This is basically this requires larger shell diameter to accommodate the split ring and however this can be for the
22:58smaller diameter can be used.
23:01The rear tube sheet is held place with the split ring in this and in this it is just directly
23:09it is easiest to remove.
23:10So, that is why these two are important.
23:14And then U type is the removal bundle without any floating head.
23:18So, this is U type means it is only the cover and cover because the tubes are inside are the
23:22U tubes.
23:23So, it is just a hand cover sometimes you may not need to open it also on the rear end.
23:32Selection guideline for heat exchanger or shell and tube heat exchanger types.
23:37Basically fixed tube sheet when the both in this significance is the both tube sheets are fixed in the shell
23:44and generally the TEMA type is BEM, AEM and NEN.
23:48These are the more popular TEMA type.
23:51Advantage of this fixed tube is provides maximum heat transfer area for a given shell and tube diameter.
23:59It also provides multiple and single passes to assure the velocities.
24:05Most important is the less costly and but costlier than the removal bundle when you are in the this is
24:15fixed tube.
24:15So, bundle cannot be removed but this is the less costly.
24:18So, cost part is more important.
24:20Generally, you use as a condenser liquid liquid heat exchanger or gas liquid exchanger or cooling or heating horizontal or
24:28vertical reboilers also it can be used.
24:32Limitations the temperature difference main limitation is the temperature at extreme can go about 200 degree Fahrenheit.
24:37It should not be more than 200 degree Fahrenheit due to the differential expansion is an issue in the fixed
24:43tube.
24:44Then you have to also install the expansion belt or expansion joint.
24:50And one more limitation is the shell side and outside tube sides are inaccessible.
24:56So, mechanical cleaning is not possible.
24:58You have to go for the chemical cleaning only in the fixed tube on the shell side or the outer
25:03tube sides.
25:05Second type is a floating head type.
25:07The one in this one tube sheet is floated with the shell or the with shell it is floating and
25:15tube bundle can be removed or may not be removed.
25:18In some cases it is removable and in some most of the cases it is removable.
25:22In some cases it may not be removable we say that S type then there is a ring.
25:26So, when S type is there you have to it is difficult to remove the bundle.
25:31You have to remove the ring also.
25:33So, this AES and BES will be the problem.
25:35So, like AEW and BWBP these are the used.
25:44When it is used the high temperature differential what is the advantage?
25:48It is about 200 degree extremes.
25:50So, it can be go above 200 degree Fahrenheit also.
25:54Dirty fluid also it is okay for this on the tube side requiring cleaning from the inside.
26:01What are the limitations?
26:02Internal gaskets leakage is a problem.
26:04Corridor fluid cannot be on the shell side and usually only confined to the horizontal unit.
26:11So, if you will find that your floating head is always the horizontal it is not a vertical exchanger.
26:19So, one important type is also the U tube bundle or U tube heat exchanger in shell and tube.
26:26So, the significance of this is basically this is in between the fixed tube and the floating head.
26:31This comes YouTube comes in between.
26:34So, in this significance is that the only one tube sheet is required.
26:38You know on the other side there is no tube sheet is only the one complete baffle is required on
26:45the end.
26:46Complete baffle which is on the other side which is for the support and only one tube sheet is required.
26:52Tube bends are U shaped and this U tube bundle can be removed.
26:57U tube design allows the differential thermal expansion.
27:00This is the best part.
27:02It is not required any floating head.
27:04It is the tubes can be expand because of the U tubes and individual tube also can be expand.
27:09Generally, the type used is BAU and AEU.
27:14Advantage high temperature difference can be used in this and might require provision of expansion of fixed tube units.
27:24Generally required a clean service easily cleaned and conditions of both the tube and shell sides are horizontal and vertical
27:31it can be installed.
27:33Limitations there are few limitations like tube side velocities can be caused erosion in the inside bends because when the
27:41tubes are U tubes.
27:42So, every time there is a there is a bend.
27:45So, this bend may the velocities in the tube side may erosion problem may occurs.
27:51Fluid should be free of suspended particles because this is U tube.
27:54So, it is something has get scaled here.
27:56It is very difficult to remove because it is not able to mechanical clean with the hydro jetting.
28:02It is chemical cleaning is required.
28:05Some because of the U tube.
28:07So, because U tubes are installed like this.
28:09So, in the center may be some U tubes may be omitted.
28:13So, that is one disadvantage of it.
28:16As we said the cleaning is chemical method has to be used.
28:20Mechanical is difficult to use.
28:21Due to U tube nesting individual tubes difficult to replace and you cannot replace the individual tube.
28:28You have to remove the complete bundle and individual tube in a straight tube you can replace the individual tube
28:36as well.
28:37But in U tube it is difficult to remove.
28:39So, tube wall thickness and U bend is thinner when you the individual wall thickness is here is different.
28:47And when you make it as a bend of it the thickness get thinner.
28:54So, that may have also the problem.
28:57Draining of tube circuit is difficult.
28:59Draining also is difficult because of the U tube.
29:02The position with the vertical position with the head upward.
29:07So, basically U tube have some advantages.
29:11But there are some limitations also.
29:13So, you have to see these limitations.
29:14And accordingly you need to select the proper type of heat exchanger.
29:20Cattle type.
29:22Cattle type reboiler is used.
29:23The tube bundle is removable.
29:25It is removable and U tube.
29:29So, you have to remove the bolting head or floating head.
29:32The shell is enlarged and allow boiling and the vapor to disengaged.
29:39Advantage is boiling fluid on the shell side.
29:42Refrigant or process fluid being chilling or cooling.
29:47It is used for chilling or cooling on the tube side.
29:49Fluid refrigerant evaporation can happen.
29:52The limitation is for horizontal installation only.
29:55Physically large and for other application is physically large.
29:58So, it is not used.
29:59It only used for the when there is a phase change.
30:03Double pipe one.
30:04Double pipe shell and tube protection.
30:06That each tube has the shell forming the annual space for the shell side fluid.
30:12And usually some external fins also used in the tube side.
30:17Relatively small heat transfer area service.
30:21And it required especially suited for the large or high pressure system greater than 400 psi.
30:29So, when you find that your pressure is very high you can go for the double pipe.
30:33And the service is suitable for the fin tubes only.
30:36And limitation is like piping and the space requirement is more.
30:40Because you have to put it in some banks as it is in.
30:44It means like you are not able to do in one.
30:47So, you have to put one more or one more or two or three in parallel.
30:52So, that takes the space.
30:55Because your transfer area is less.
30:58So, you have to give the multiple exchangers for the double pipe.
31:03So, here we are for the shell and tube we have completed the selection guideline.
31:07For the shell and tube detection just different types.
31:11And we will see in the upcoming lectures.
31:14What are the guidelines for baffle spacing.
31:16What are the guidelines for the tube bundle.
31:19What are the guidelines for the tube sheets.
31:21And the shell.
31:24So, stay tuned.
31:28Thanks for watching this video.
31:30If you have any question write it in comment box.
31:33We are happy to answer it.
31:34If you want to reach us on conceptengineering2025.gmail.com
31:39We will answer your question.
31:40Link of all session for module 1 pressure relief wall are given in the description box.
31:46And this for this module 2 heat exchanger also given in the description box.
31:50So, other sessions will come subsequently.
31:53And we will add the links in this video description.
31:56If you like this video share it with others.
Comments