 so as i told you we will do one problem very simple problem very very simple it is nothing to do with what we have done with the complicated equations for complicated equations for the problems to be done i have actually asked you sent you last night the assignment so that is why particularly the problems given in smith the solved examples please go through first go through the solved examples and then try to solve them the problems which you have given okay then i tell you definitely if you are able to do on your own as a group one or two also you can do together okay two three but not only one doing and other people just sitting all three discussing and doing will be very good do it then it will boost your confidence like anything that means not only this design if you are able to this design even distillation column design absorber design all these things will look very trivial if you are able to take up this design to even the mechanical design part mechanical design part means you calculate what is the total amount of catalyst then you have to think how do you put this total amount of catalyst what should be the diameter what should be the height and how do you put them support because when is a packed bag you have to support the packing on something that is the distributor plate otherwise if we simply take without any holes a plate and then support it you cannot put anything no the gases cannot go inside no perforated plate perforated plate design also is very important which we have never told you in during distillation design okay that is why i told you know i think my example all our Indian movies where we stop where we stop after marriage subhum means in a marriage there must be marriage all people laughing that is the last scene in every in every movie they don't know that real problem start only after marriage okay similarly here finding out ten plates is not much for distillation column how do you put these ten plates okay what is the geometry of these these ten plates so that is the problem how do you fix these plates to shell how many problems much more difficult you know marriage problems you can solve but these problems you cannot solve so easily okay because you have counsellors and all that for marriage but i think here distillation column design only you have to do with a degree if you go to that is what i am telling you know you cannot go to consultant if you have a chemical engineering degree right where do you go right someone can go if he doesn't have a chemical engineering degree he can go to consultant no problem at all okay good so that is why it will really help you in understanding if you are able to solve and if you have time please try that two dimensional model also where for finite difference method is used it will be very good good but for that you have to spend some time right but unfortunately i have given this time non catalytic reactor design if i could have given the actual catalytic reactor design as a project those techniques you could have learnt but this is totally your imagination so that is why this non catalytic reactor what i have given that is incineration is totally you have to imagine everything only thing what i have given is how much yeah waste is to be incinerated waste to be incinerated that's all okay so you have to choose the system you have to find out what is the carbon content and you have to say no please don't give that you know the because this since it can be land filled incineration not necessary you know two lines design is over you are not allowed to do that it is a non catalytic reactor you have to design it yeah and the reason also why you can't do that is nowadays there is no place for landfill particularly in Andhra there is no place because every politician has taken thousands of acres so i think there is no place to put even this waste solid waste okay in Tamil Nadu also no they are not because i told you know all Indians are brothers and sisters so their ministers here also they have brothers and sisters so these people also have occupied but anyway technical solution you have to give not simply landfill okay yeah good so this problem simple problem i will try to do in a please take this problem i will dictate i don't have to write the whole thing a second order reaction a going to r you have calculators with you know yeah a second order reaction second order reaction problem a going to r this is second order reaction second order reaction is studied the second order reaction a going to r is studied in a recycle reactor please see in a recycle reactor good in a recycle reactor with large recycle ratio and the following data are recorded and the following data are recorded so void volume of the reactor void volume of reactor 1 liter 1 liter weight of the catalyst used weight of catalyst used 3 grams feed to the reactor to the reactor is let us say u0 equal to 1 liter per hour initial concentration CA0 is 2 moles per liter 2 moles per liter and CA out exit concentration exist concentration C out equal to 0.5 moles per liter okay so then the problem is a find k that is 1 calculate k value okay other one is b how much catalyst is required in a packet bed reactor for 80 percent conversion of in a packed bed reactor for 80 percent conversion of 250 meter cube 250 meter cube per hour of feed per hour of feed of concentration feed of concentration 1 mole per liter no recycle is used full stop there no recycle is used the other one is part C repeat part B if the reactor is packed with one part catalyst to 4 parts inert solid this addition of inerts helps maintain isothermal conditions and reduce possible hot spots okay so the other data which I have to give you is XA equal to 80 percent and V0 equal to 250 meter cube per hour and CA0 equal to 1 mole per liter you have to find out what is W right okay so now you have the calculators right with you most of you yeah it is a second order reaction please see that I think you know it and recycle reactor okay so what we have here is recycle reactor something like this this is the catalyst 3 grams we put it goes small amount is taken that is recycle okay so I can close also this this is W 3 grams W 3 grams and of course the feed is given U0 velocity is given as 1 liter V0 not U0 volumetric flow rate V0 V0 is 1 liter per hour per hour and CA0 equal to 2 moles per liter anything else is given yeah that is all CA out here equal to 0.5 moles per 0.5 moles per liter good so what is the problem now see this is typical Levenspiel problem I am just indirectly trying to tell you you know examinations right all typical Levenspiel problems you starting from second second first semester first chapter does not have any problems then onwards he gives some clue in the beginning and you have to get some information from the first part and then use that first part in the second part to calculate something else okay so first part he is asking you K and data given recycle reactor is given so now what equation you use to calculate this is ideal plug flow because nothing is told about non-idealities right simply ideal plug flow and this is how most of his problems are formulated because this is what is happening most of the time in industry if you are developing a new process in the laboratory you conduct some experiment get the kinetic data use that kinetic data to finally scale up the industrial process okay and here to avoid complications we are simply taking plug flow isothermal there is no temperature variation and all that so the simplest problems we are trying to attempt so that you know slowly you can graduate if the complications are increasing later okay but currently it is only the simplest problem isothermal plug flow and it is recycle reactor with a large recycle ratio what is the meaning of that then what is the equation you use to calculate K it is second order reaction please remember you are okay and you do not have anything no calculator nothing but you do not need calculator also I think it is calculations are very simple very very simple they are not that difficult w by f A not equal to x A by minus r A which is nothing but k C A not 1 minus x A correct no this is the equation okay substitute the actual units and then try to find out I say substitute the actual units there f A not is moles per second moles per hour later hour gram that is the one later square mole gram catalyst hour yeah and if you write 2 I will not give you I think not even half mark there negative marks only will be given if you are a shokumar if you just write only 2 got it correctly later square yeah so that is the one actually so this will be after substitution of all I was simply writing here 2 later square mole gram catalyst per hour so I just want to tell you you know because this is a peculiar unit you would have never imagined that this kind of units will be there for k values because we always know for second order someone was telling you know mole later hour yeah that is what what we remember that is L K G long time back over okay so for heterogeneous system you can have anything any units okay good these right you got it Kavya yeah Anand Kumar no okay so what is the next one next one we have this is A in B we have the packet bed okay you have to find out packet bed where you V not given as 250 meter cube per hour V not C A not equal to 1 mole per later okay and X A equal to 0.8 question is what is W now this is a packet bed what is the equation use yeah but what is the other side yeah again W by F A not equal to integral yeah now you say you integrate and tell me W by F A not equal to 0 to X A D X A by minus R A it is second order reaction second order reaction anyone Renitha anything your handwriting is so beautiful I say I want to see she writes very clearly 125 for 250 grams correctly substitute all that you also got same thing how much you got 500 into 10 is to I mean into 10 to the power of 3 grams 500 grams 500 kg correct no yeah but what do you mean by too high how much you expect how much you expect I say it is industrial reactor 250 times 250 meter cube yeah so that is why it is more only yeah check whether yeah K value 2 see yeah and the problem is that you know you think that you are right and you go to hostel and tell that he gives always less marks okay not only you all I told you know all Indians are brothers and sisters there is no change right so whatever you write I have to give the marks or not the correct answer 500 500 kgs per meter cube okay now you tell me how do I put this 500 kg per meter cube after marriage okay yeah so 500 kgs we got the catalyst so how do I now choose my dimensions for the reactor you should have some dimensions know some days some diameter and some height if it is a cylindrical can you also use square cross section and some height no why in the corners are yeah corners are always bad even if you have sharp corners better come out of that okay we also have sharp corners so we want only rounded personality but I think round reactors we can't use because flow is very difficult there so that is why cylindrical reactors we use okay which represents us I think I told you know last semester all human beings can be classified into three groups first group is straight lines in the class I think Renitha is straight line y equal to MX plus C okay yeah only one dimension you have other dimensions are not there right very tall and lean people I say okay where one dimension is seen earlier in very old movies there used to be in Telugu there used to be an actor Ramana Reddy excellent representation of one-dimensional model you know single straight line okay so they look almost something like this you know that is the straight line okay and other category is cylinders these are normal okay all of us and other category is somewhere legs somewhere hands not as you already I used to see always this spherical coordinates with that you know that Adnan Swami or someone was there what that yeah he's I think now he reduced it I think maybe 250 kgs 120 kgs exaggerated multiplied by 2 okay so 250 kgs I think you always you can see now you can start looking in the road when you are moving you can see most of the time straight lines cylinders spheres now in India this spherical coordinates are increasing all of us starts here like this okay third category because they take almost highly nutritious food so that is why third category means spheres only yeah that is what I am telling if you take too much fat and all that you become like that okay so earlier it is not much maybe 50 60 years batch a bag state lines were there but I think spherical coordinates are not that much for human beings but nowadays it is very happy you know to have that kind of coordinates what I say you see most of the young boys and girls it is not missions I think you know I tell you in our society the problem is that when we were born for each parent minimum it is 7 or 8 okay children right yeah not only starvation attention is not there I think mother also don't remember to which kid he she has fed okay so but on the average everyone is equal sometime they will get some food okay but nowadays it is 0.5 or 1 children yeah 0.5 children so are there okay one children but now everything and also now most of the time now all the parents are very well well off that means they have sufficient money and all that because mother and father both of them are working so many things are happening both of them are well educated so now everything they want to give to the kids if there is a burger immediately advertised in TV they will run through that shop buy and then put in his mouth or her mouth okay Krishna sweets advertisement go buy 10 kgs of Mysore Park put in his mouth or her mouth so what will happen after sometime he thinks that my god I have to take everyday 10 kg sweets that buy you know kid he does not know many things and also any advertisement in beautiful clothes like jeans pant that fellow will be 1 inch and you know so they they will design I think 0.4 inch jeans pant so mother father will run to that jean shop you know it is a express mall and what are other malls in either some other malls are there no lifestyle or many places so they go buy and then even he is weeping he will put or he will parents will put and anyway car and all that that is the same arrogance which has come to the society so that is why if he comes to class 1 he thinks that he must be the first everything you should get right or wrong whether he writes are wrongly like you are telling no 200 or 100 whatever you write I have to give the marks because parents are giving everything okay so like that whatever exams you write like that school education will be over and you feel that you know you are the top and this is how the society is moving because this arrogance has come because of the parents we have now only 1 or 0.5 we have not mentioned the particle size for example okay there are so many assumptions okay what are the assumptions particle size is not given 3 kg is told there what size not known okay but will it be different size or same size we have to use laboratory have taken some data using 3 grams and the 3 grams also we will have some size definitely is it the same size or different size you use exactly same size you have to use what will happen if I do not use same size I will use something different you do not know whether there may be mass transfer effects if you take large particles mass transfer effects okay and if you take very small particles pressure drop effect because again you have to put in the packet bed know so all that so that is why there are so many assumptions here which we normally do not tell we will just give you as an academician this is the problem I have not told you in packet bed I mean packet bed behaving as plug flow okay so there are so many things which we have to really use if you go to reality reality is your industrial reactor where I have to put this 250 kg is 250 500 kg is where first of all you have to question what is the particle size right so the same size only you have to use which you should hear because otherwise your kinetics will be different your k value may be different okay because intrusion of diffusional problems all that may come right so that is the one then what is the diameter you put you have some thumb rules I just want you to recall your memory we have some thumb rules already yeah so if the diameters let us say 6 mm particles which we have used so then minimum diameter should be how much yesterday we have some criteria R by R by DP less than 4 what will happen why why why that means you have uniform distribution okay so you should maintain that much okay good but the problem now is if you take only that diameter and pack 500 kg it will go to the top to the moon okay so that is why as an engineer you have to balance because I have taken the data using this kind of condition particles and diameters particle size temperatures flows and all that can I maintain the same kind of conditions and reduce the height also right otherwise pumping cost and all that will be per unit length you know delta P all that so that is why most of these design problems are having open-ended solutions if you are a very good engineer you design it wonderfully it is like architect constructing the house you know if he is a good architect you can see the beauty of the house if it is a lazy fellow we can also see the laziness of the house so that is why simply leaving here 500 kgs and then finding out okay somehow you put because we never tell you how to put in fact right starting with the distillation even for heat exchangers right we normally give you in the class find out what is the total area you say 10 meter square how do you put this 10 meter square what is the diameter of the tube and how do you arrange these tubes okay so all these are the problems which you have to note down somewhere right so that is why packet bed reactor even though we have used simply this is the packet bed reactor nicely all academicians are responsible for this also because we never tell the we also live in only real imaginary world not in the real world okay so if I am able to really give you what is this size how it should be I am giving you the general thumb rules what should be the minimum length because here we have plug flow diameter we told at least minimum length how much you have to maintain so that you will have plug flow almost L by D greater than almost plug flow if you do if you use that much that means if you are using 6 mm particles okay 190 means 200 you take right 200 into 6 1.2 meters that is minimum height if you are able to go beyond that you are happily going for plug flow but the problem is if you have more and more lengthy reactor then you have the pressure drop more and more and you cannot afford that because whatever you are getting gaining the what is that yeah if you get more money more money also will go so that is the reason why you have to really balance it good okay so these are the things what we have and yeah another one next one see because I know you are hearing as if it is Harikada kalakshepam or something like that okay but unless you write somewhere you will not remember afterwards all the questions what I raised what should be the height what should be the diameter you know in fact how do you design the distributor plate you need one distributor plate at the bottom and one distributor plate at the top here here you should have one distributor plate here you have you should have another distributor plate and the another question is Kavya would you put this packed bed horizontal or vertically yeah probably why vertical he says like this and I will also ask if you say horizontal why horizontal why correct that is why usually all reactors are if I put horizontal it is very good I say I do not have to pump at all right pumping cost is very very low if I put horizontally what do you mean by contact I think it is going you know you see simple things I say very very simple things why do you want to put all reactors as proposed only vertical we got to put horizontal not only that I can also tell you actually mixing is bad for reactor why do you need mixing you cannot have mixing contacting between what and what yeah by putting horizontally what will happen in the reactor how the contact is less there is no two phase only one phase you know for example gas yeah what will happen if I have for example distillation column horizontal distillation column instead of vertical I will put horizontal yeah because it is two phase very clearly seen that liquid is at the bottom gas is at the top and then the contact is only where interface so that means you are not able to generate bubbles generate large amount of surface area and contact the liquid something like that can you also think when you put horizontal packed bed it is after all catalyst okay and your packing you cannot have exactly yeah there will be slightly some gap between the top wall channeling channeling channeling is the main reason because when you put horizontally the particles try to consolidate themselves and then you will have definitely something or other on the top more wide edge so when you have more wide edge more and more gas will try to go on the top because less resistance okay so that is the reason why most of the time in all these case I think as Prabhu said you know most of the time we use all columns vertical only in chemical engineering we do not know x direction all chemical engineers know only y direction distillation column same thing absorption column same thing all extraction columns all mass transfer heat exchangers by the way why we cannot have put vertical we cannot have put vertical why horizontal that is right question is right most of the time they are surface area you are putting all the tubes know all these surface area is given by the number of tubes inside outside you have a shell that is the correct answer why why it does not matter why it does not matter it actually depends on what temperature gradient depends on what is the contact between liquid and solid tubes it does not matter if you are able to fill up the entire shell and also entire tube if definitely matters if you have two phase flow again in heat exchangers particularly when they have steam generation yeah condensers and all that you have to go for vertical condensers horizontal condensers no okay so you see these are very very simple things but we never bother to give some attention to that okay so that is why I think equipment design is one of the wonderful subjects for example all these things will come there know this is process design in fact what we calculate to 500 kgs and then just leave it that is the process okay using that the equations and all that this is the amount I got but equipment we design only will tell me how do I put this 500 grams or 10 meter square area for example heat exchanger okay or 10 plates or 20 plates how do I put it okay and what kind of plates I think you also know that in distillation itself we use sieve plates bubble caps and sieve plates with down comers what is the difference between sieve plates with down comers and sieve plates without down comers remember problem any time where where we will weeping occur in which plate sieve plate or why why why weeping should occur you are not supposed to operate in that regime that is why floor regime maps are given to you you are not supposed to operate in the where you have the weeping of the liquid correct no that is not operational regime and you cannot also go for flooding regime where you have too much vapour phase and too less liquid phase and it is not allowing liquid to come down that that also you cannot operate you should not so when do you choose what also is very important when do you choose for example sieve plate with down comer the best thing is sieve plate only why because in each sieve each perforation will will definitely develop one bubble so that bubble will contact the liquid which is just above the plate now in sieve plate what happens is the liquid and gas both of them have to come through the same sieves right so through some sieves gas will go through some sieves liquid will go right so that is the reason why you have very quick flooding and there is no good contact because if you take 2 meter diameter 2 meter diameters also can be the diameter of distillation columns so one corner you will have only liquid coming down another corner only gas going up you will not have uniform distribution of exact distribution of gas bubble generating throughout that is why what compromise is okay let let us allow the liquid to go through down comer and allow only gas through the sieves where you have each and every bubble forming then that will contact but anyway above that you know there is a flow here and then comes out and the bubbles are going and then contacting the liquid one of the best designs then you have other one that is packet beds packet bed distillation for example when do you use packet bed distillation when do you use plate distillation plate column distillation so many things are there even heat exchangers when do you use coil type heat exchangers when do you use simple shell and tube okay and plate type heat exchangers are available plates one plate next plate next plate goes like this and within the plates you will have again another volume available for flow so many wonderful design there is no limit for chemical engineering thinking you think that all the things are over in chemical engineering limitation was only your brain not the subject in fact in any subject this is the limitation not the subject itself okay good so these are all the things but now we are not discussed see no oh yeah let us discuss okay yeah see repeat pot B if the reactor is packed with one pot catalyst what will happen will the conversion change that is all only weight of the catalyst sorry weight of the total amount of solid will increase but it is not going to change the conversions right and because you are sending the same thing and only thing why we are doing that is for maintaining isothermal conditions this is what I mentioned also sometime earlier to maintain some isothermal conditions people always but if your volume is so precious why should I use five times larger than you know the active catalyst alone if that is more important then I think you have to look at only one part of catalyst and then try to live with that but if volume is not the constraint for us then you can go for more volume maintaining isothermal condition is thermal is easy to design and no temperature controls and all that so that is the reason why but everything is again economics finally you have to do this this this this and compare which one has the best system and what is your objective function cost finally cost everything is money okay but without doing anything we want money you know that is what is nowadays our trend I should not do anything but I should get crores and crores of rupees okay with that attitude we cannot design anything but I think you have to know all this do everything and then try to find out which gives you the minimum cost of production then you can sell with some profit and you will get some profit after the design okay so I thought I will start fluidized but I think we will stop here okay so now I think I have thoroughly done packed beds but the thoroughness will come to you provided you work hard okay please spend some time and all of you are not taking 100 courses okay and it is varying from 1 2 yeah 1 2 maximum 3 or 4 correct know 4 so that is why it is not too much load because we have 24 hours per day we cannot ask more than that so then I think definitely you can spend some time in learning this okay so the good so I think we will stop here and then meet on Monday with fluidized beds thank you