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1. Basics of Heat exchanger
2. Classification of heat exchangers
3. TEMA class
1. Basics of Heat exchanger
2. Classification of heat exchangers
3. TEMA class
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LearningTranscript
00:00Hi friends, welcome back to our channel concept engineering flux for the pressure relief valve
00:06before starting this.
00:07I hope you have already watched our module on pressure relief valve.
00:13Now we came with the module 2 on heat exchangers.
00:17In this module we will cover all the topics from concept to detail design including the
00:23simulation or you can say HTRI how to design an exchanger on HTRI.
00:28So, let us start with the session 1 introduction to heat exchanger part 1.
00:34If you are new to our channel, please like and subscribe it.
00:42So what is heat exchanger basically economics of any plant operation is often controlled
00:49by the effectiveness how effectively you are recovering your heat and cold source.
00:56So, if any plant is operating it should be operated good economically viable then it has to be
01:05recover the complete heat from the process or complete cold available in the process.
01:11So, the utility requirement like steam and cooling water can be minimized.
01:16that is the heart of your plant operation then equipment that efficiently convert the recovery
01:25or converts the recovery of heat is known as heat exchanger.
01:29So, which helps in recovering that effect heat or cold that is your heat exchanger.
01:36And theoretically basically heat exchanger is a mechanical equipment in which heat is exchanged between
01:41the two fluids having temperature gradient.
01:45So, heat exchanger is an equipment which recovers the heat.
01:53Heat exchanger is an equipment which effect the transfer of heat from one fluid to another
01:59fluid through a metal wall.
02:01So, there are tubes or there can be a plates by which heat can be transferred from one fluid
02:07to another fluid.
02:08The equipment is called heat exchanger.
02:12If you know that the smallest heat exchanger less than 1 watt is or you can in miniature cry
02:19coolers or in infrared thermal imaging system it will be used for the superconducting and
02:27electronics application.
02:28So, which will be the less than 1 watt and the biggest or and the largest one is like
02:34more than 1 gigawatt are the boilers or condenser for any process unit.
02:52So, why heat exchanger fundamentals are important why we should learn the heat exchanger fundamentals.
02:58Because the heart of a proper design or a proper process design is to interpreting a process
03:05requirement into a properly arranged or sized mechanical hardware.
03:09So, whatever the process design we do in based on that process design the final outcome is
03:14a mechanical hardware or any mechanical exchanger or a vessel is getting manufactured.
03:18So, that should be get properly manufactured or that should be properly get design.
03:22Otherwise, we will design something which is if it is not suitable for your layout or it
03:28is not suitable for due to the height or length of it.
03:33We can as a process I can I can design an exchanger with a 10 meter tube length but which
03:39is not
03:40practically possible to install because of the space constraint or some other constraint.
03:45So, when we do that is why we should know the fundamentals of that process design which will also should
03:54be practically possible in to manufacture it.
03:58So, that way process engineer has to think not only to design it.
04:04So, nowadays generally design of heat exchanger is done through a software or a computer program
04:10specifically like STRI or ADS and the engineers does not know the fundamentals of it.
04:19Because STRI or ADS you can put a 3 or 4 values or you can get a
04:23exchanger design but how to verify that what are the design given by the software is correct or not.
04:30So, for that we should understand the first the fundamentals of heat exchangers.
04:36So, unless the designer has some knowledge of what specific computer program can accomplish on
04:43what specific heat transfer equation or concept the program may program is based or which of
04:50these concept have been incorporated into the program the user designer can be a flying blind.
04:56So, if you don't know how it works then it is like you are flying with a blind on your
05:03eyes.
05:05So, if you don't know the fundamentals you will going like a blindly believing on the software
05:18and then if that what are the software output comes if it is not practically possible to
05:24manufacture then it is a disaster.
05:29Applicable codes and standard.
05:31So, TEMA standard for the tubular exchanger manufacturer association.
05:36This will be used for the heat exchangers.
05:38Then API 660 which is used shell and tube exchanger for a general refinery services.
05:44API 661 air cooled heat exchanger for general refinery services.
05:49Then ASME section 8 it is for the construction of pressure vessel and there are some other standards also.
05:53But majorly these standards are used for the design of heat exchanger.
05:58So, what is TEMA?
06:02The standard for the tubular exchanger manufacturer association TEMA is the only assembly of unfired mechanical standards.
06:11Unfired mechanical standards means it is for the unfired there is a fire deter and the unfired heat exchanger.
06:17For that only this TEMA standard is used including the selected design details and recommended practices are given in TEMA.
06:25The process engineer needs to understand the terminology of heat exchanger equipment manufacturer in order to properly design, specify, evaluate
06:34bits and check the drawings of this equipment.
06:38So, process engineer should understand this standards to evaluate, specify and check the drawings from the vendor when it comes
06:48to your review.
06:50The standards are updated every 10 years.
06:54This TEMA standard updates every 10 years and the standard do not designate and recommended any thermal design method or
07:01practices for specific purpose application.
07:03But, but give the outline basis of heat transfer fundamental and list suggested following factors and wide variety of fluid
07:11and process services.
07:13So, these standards gives you the guidelines basically.
07:17So, TEMA gives the classes for the refined for the exchanger manufacturing.
07:23So, there are three mechanical standards in TEMA.
07:27So, class R, class C and class B which represents the varying degree of mechanical details for the design of
07:35the process plant application and its severity.
07:38The code is designated by the TEMA 99 edition for mechanical design and fabrications.
07:46So, RCP also, this RCP classes are includes the construction and design are identical for shell diameter not exceeding 60
07:56inch and maximum pressure of 300,000 PSI.
08:01So, this RCP construction guidelines remain same for this type of exchanger which where the shell diameter is less not
08:09exceeding 60 inches and maximum pressure of the exchanger not exceeding 60 inches.
08:13So, this is more than 3000 PSI.
08:16So, basically R is designated to severe requirement of petroleum and other related processing applications.
08:23Petroleum or you can say oil and gas or refinery R for refinery.
08:28C indicates the general water rate requirement and commercial and general process applications.
08:35And B is the specific design and fabrication for chemical process services.
08:41So, based on these three if you are doing any exchanger for the refinery then you have to put R
08:48and if it is a general purpose in a small water rate or anything which is not in a refinery
08:55or oil and gas plant then you can give as a C.
08:57And if it is a chemical plant and a specific design then it should be given as a B.
09:04Classification of heat exchanger.
09:06Basically heat exchanger is classified in four ways.
09:19So, classification of heat exchanger based on the construction.
09:28So, first type is recuperative heat exchanger and the second type is regenerative heat exchanger.
09:35So, recuperative heat exchanger basically is the
09:38It is separating the two fluids by means of any tube wall or tubes or any plates anything and the
09:48flow of the fluid passes simultaneously.
09:51So, that is the recuperative heat exchangers.
09:54So, all the major exchanger used in the industry like tubular exchanger, extended surface, air fin fan and plate type
10:02heat exchanger are all are recuperative type of heat exchangers.
10:07So, regenerative heat exchangers, this exchanger has only single set of flow channels through the relative massive solid matrix.
10:15So, what happen when the hot and cold fluid passes through the matrix alternatively.
10:19So, one time hot fluid will pass and another time cold fluid will pass.
10:23So, when hot fluid will pass, it transfer its heat to the matrix and then when cold fluid passes through
10:32it, the heat from the matrix will transfer to the matrix.
10:37So, this way this regenerative heat exchangers work.
10:41So, generally like a catalyst or anything that type of thing where the heating and cooling media goes alternatively that
10:48is called a regenerative heat exchanger.
10:51So, classification based on construction continues.
10:54So, as we see in the recuperative exchanger, these recuperative exchangers are basically divided into two major parts indirect contact
11:03type and direct contact type.
11:05Direct contact type, it means it is like mixing of two fluids together, immiscible fluids together or vapor and liquid
11:13mixture.
11:14So, direct contact of two liquids that is comes under direct contact.
11:18In this mass transfer also may happen.
11:20In indirect contact, the major one is tubular which is most of the industry used.
11:25Extended surface like fin fan and others, this is also used widely and plate type of heat exchanger.
11:31This is comes under indirect.
11:32So, two fluids will not get mixed.
11:35They will be separated by tubes or extended surface or a plate.
11:40So, tubular will have shell and tube exchanger, spiral tube exchanger, fixed tube, U tube.
11:45There are so many types in tubular, double pipe.
11:48In extended fin fan tubes or fin plates, fin tubes will be used in air fin fan and fin plates
11:55will be used in PHE type of exchanger as well.
11:58And plate type is gasketed plate, spiral plate, lamellar plate.
12:02These are some example of indirect contact type.
12:08And there is a regenerative type also we have seen earlier slide.
12:12So, in regenerative, there are two major exchanger.
12:15One is rotary regenerator and one is fixed matrix regenerator.
12:19So, we in the first slide we understand that in this alternatively hot and cold fluid will be transferred.
12:28So, in fixed matrix, the matrix will be like any matrix will be in a vessel or any box that
12:36will be take the heat and then in the second round the cold fluid will pass and that will take
12:43out the heat from that matrix.
12:44That is a fixed matrix one and for rotary one, matrix itself will move.
12:50So, suppose this is a heat, this is a matrix made up of some plates or something, this matrix itself
12:57is rotating.
12:58So, one side the hot fluid passing.
13:01So, when hot fluid passes, this matrix takes the heat and when this matrix rotates, it comes on this section
13:08where the cold fluid is coming.
13:11So, in that case, this matrix moves here and then cold fluid will take that heat, which is transferred from
13:18hot fluid to the matrix and then from the matrix, the heat will be transferred to cold fluid.
13:24So, this is called a rotary regenerator type of heat exchanger or you can say regenerative type of heat exchanger,
13:30which are not generally seen in the various industry, but these are the typical examples used in some specific industries.
13:41The classification of exchanger based on the process are simple, the indirect contact type and the direct contact type.
13:48So, direct contact type also comes under recuperative exchanger and indirect also, these both are coming under recuperative type of
13:56heat exchanger.
13:56So, indirect contact type, we know the direct transfer type, in this we can have all the tubular exchangers everything
14:02and storage type means the heat is getting or you can say fluid is transferred to this storage and hot
14:10fluid and then that heat will be transferred to that particular equipment or matrix and then it will be again
14:17transferred to when the cold fluid is transferred that heat will be transferred to the cold fluid.
14:22Similarly, fluidized bed, so all the catalyst beds, if you have a catalyst, the hot fluid will transfer, it will
14:29heat that catalyst and when cold fluid comes, the heat will be given to the cold fluid from the catalyst.
14:37So, this is like regenerative type of exchanger.
14:41So, this is like a regenerative type of exchanger, but it is a indirect contact.
14:44Direct contact type are like invisible liquids or invisible fluids mixed together and transfer the heat, gas and liquid mixed
14:53together and liquid and vapor.
14:54So, that in this direct contact type with the heat transfer, mass transfer also can occur based on the which
15:02process you are using.
15:05Classification of exchanger based on the flow arrangement.
15:08So, first is parallel flow.
15:11So, hot and cold fluid enters at the same end and flows in the same direction and exit on the
15:17opposite direction.
15:18So, hot fluid and cold fluid both enter from the same direction and flow in the same direction also, that
15:26is a parallel one and get out on the opposite side of the exchanger.
15:31So, if you see the hot fluid will come like this and cold fluid temperature is like this.
15:37So, in this case cold fluid temperature will never go above the hot fluid temperature.
15:42So, final temperature difference is low and this is a little bit a low efficiency process like when you give
15:48parallel flow to the exchanger, parallel flow in exchanger.
15:54So, second type is counter current, counter current flow or counter flow.
15:59So, hot and cold fluids enter at the opposite ends and flow in opposite direction.
16:04So, this is a most efficient arrangement and allows cold fluid exit temperature is higher than the hot fluid exit
16:10temperature.
16:11So, if you see the hot fluid is coming from this side and cold fluid is coming from this side.
16:16So, it is a counter flow.
16:19So, it is a counter flow and if you see the temperature graph on for the A to B.
16:23So, the hot fluid temperature comes down here and cold fluid temperature is cold fluid comes in opposite direction.
16:31So, its temperature can be higher than your outlet temperature of your hot fluid.
16:36So, hot fluid temperature is this suppose your cold fluid temperature can be higher than that.
16:41That is the significance and this is the most efficient arrangement for the heat exchanger.
16:48The third type is cross flow arrangement where the two fluid passes perpendicularly.
16:53This general arrangement is available you can find in all the fin fan coolers where the air is perpendicularly passes
17:01through the exchanger.
17:05So, it is like this the fluid is passing through the tubes in this way and air can pass in
17:12perpendicular to it.
17:14In air fin fan it can be vertical direction.
17:17So, if fan is put on the top of it.
17:19So, if you see the temperature wise here also the temperature in perpendicular case generally not crossing the cold temperature.
17:27It is not crossing the hot side outlet temperature and this is so it is almost same as it is
17:34actually this process is in between efficient between the parallel and counter.
17:39So, it is a middle one it is more than parallel flow it gives efficiency and lower than the counter
17:45current flow.
17:46So, this is the classification based on the flow arrangement.
17:51So, type of exchanger based on the service or you can say classification of exchanger based on the service.
17:56So, first type is general exchanger the heat exchanger heat between the two process streams without changing any phase.
18:04So, that is we called as a exchanger or you can say cooler.
18:09So, in this cooler also it cools the process fluid without changing its phase.
18:13So, it can be called as cooler or if it is not cooling anything if it is just exchanging the
18:19heat but at the moderate temperature then it is called an exchanger only.
18:23So, if you see the temperature graph so temperature hot fluid temperature comes down and it generally
18:31it is a counter current flow.
18:33So, cold fluid temperature is also increasing.
18:37Condenser condensers are where the it condense the process vapor stream.
18:42So, in this case the vapors are at saturation and when it pass through the condenser or it pass
18:49after the exchanger it phase changes.
18:52So, it will cool the vapors and condense it.
19:00So, if you see if vapors are at saturated condition when you pass the cold fluid through the exchanger
19:06the vapors which are at the saturation it will get condensed.
19:09The temperature remains same but it will get condensed at the saturated temperature.
19:17Similarly, reboiler, reboiler provides the latent heat of vaporization to the bottom of distillation
19:23and it also changes the phase.
19:26So, in reboiler the liquid is at saturated condition.
19:33So, it will give you the vapor.
19:35So, temperature will not change but it will change the phase of the fluid and hot fluid it
19:41may be a steam or may be a fire heat or anything that will give you heat and it will
19:45get cooled.
19:47So, it is not fire heat or this is like for the steam graph.
19:50So, steam comes it will give heat to saturated liquid and then latent heat it will be based
19:56on the latent heat it will be vaporized.
19:58Pre-heaters, pre-heaters are the steam or hot process streams to heat or vaporize vaporize
20:04the feed to the of the process unit.
20:07So, it is like a preheating you can use an overhead vapors to heat the feed of the same column.
20:15So, that is called preheaters.
20:17So, in this way type of exchangers are or you can say classification of exchanger based on the service.
20:25Based on the classification of exchanger we can finalize that or we can consider that based on the transfer process
20:34like indirect transfer which is normally used.
20:37Then based on the construction tubular wear is more common.
20:40And then based on the flow arrangement counter current is more common.
20:44And based on the service all the type like exchanger, cooler, condenser, reboiler and pre-heater all these are common
20:51in refinery processes.
20:53So, based on this classification the most suitable exchanger is the shell and tube heat exchanger.
20:59It will have a various types we will see in upcoming sessions.
21:02And we will study this shell and tube exchanger in detail even the design of shell and tube exchanger.
21:07Also we will study the air fin fan cooler and plate type heat exchangers which are the commonly used in
21:13process industry.
21:15So, here we are concluding the classifications of heat exchangers.
21:22Thanks for watching this video.
21:24If you have any question write it in the comment box we are happy to answer it.
21:29If you want to reach us on conceptengineering2025.gmail.com we will answer your question.
21:35Link of all session for module 1 pressure relief wall are given in the description box.
21:40And this for this module 2 heat exchanger also given in the description box.
21:44So, other sessions will come subsequently and we will add the links in this video description.
21:50If you like this video share it with others.
21:55Bye.
21:56Bye.
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