 we will start now in the last two classes we have learnt two things what is the first thing we learnt first thing we learnt was that we do not have much knowledge in chemical reaction engineering and chemical reaction engineering is the basis for entire chemical engineering okay and then second thing atleast I asked you to learn is the attitude for learning or the pleasure in learning so it is very easy to waste time in anywhere in 80 meters also it is nowhere different you have many many different things here to waste your time so but without going to that mode of wasting time you try to read the books or try to read some papers or you know whatever interested problem for you or interested course okay spend more time with books rather than with you know other things computer also you should not spend so much time unless it is really required computer is one thing which distracts a lot so these are the things we learnt that means you know I try to change your mind a little bit for active learning right and two years particularly for M Tech is a very short time and three years for MS and MS people also can submit within two years also theoretically speaking one and half years you can submit the thesis MS people right so that is very short time to learn but it does not mean that you stay here ten years or twelve years okay so that is also too long time to learn also because I think you know you will get bored and then slowly lethargy everything will come so that is why there is optimum time you know for you two years for M Tech and three to four years for PhD then that time should be very optimally used so at the end of that four years you should see yourself a different person if you look at yourself particularly in the mirror okay that is why everyday you see mirror and try to change the try to look at that change whether when do you have that change you will suddenly have all this kind of things will come most of the time suddenly okay you discover at least suddenly it the progress may be change in that change may be very very slow but suddenly one day you discover that yes now I changed that means change means not physically your nose will not change or you will not have three eyes okay and then four legs or ten legs so you do not have but only problem is that your attitude in learning and suddenly that beauty of learning something that happiness you will see that happiness will come when you learn some concept on your own or after discussing with some people everything you do not have to learn on your own so that is the happiness you have to search for during this time here then I will tell you one concept thoroughly learning okay either with discussion or on your own then you yourself feel that happiness and no one you cannot share that happiness with others even if you go and tell your friends that oh my god I am very happy now because I learnt this a small concept which I never knew earlier I had lot of difficulty in learning that concept but now suddenly I see the clarity in that concept they may think that I am mad fellow I think you know you will be talking like that that they may say but that your own pleasure is more important for you so these are the things which we have learnt in the last two classes and now we thought that we do not have that much knowledge in chemical reaction engineering and chemical reaction engineering is the main topic in chemical engineering that is the only subject which can differentiate with any other engineering I will tell you why you know in course of time but right now I think I do not want to explain that now itself so it is unique course that is why it needs some background of asking even what is chemical engineering okay so you know that without chemical reaction you cannot produce anything that is why my first question would be I will write the questions here I do not use most of the time this PPT I use only this boat so the first question is what is chemical engineering and second question also we will ask that what does a chemical engineer do yeah the third question is how does any chemical process any chemical process okay so actually by looking at the questions you can learn a lot that is why you have to question everything whatever you want to learn first question then if you get the answer to that question correctly then you know what is happening there so you have the sufficient knowledge then the fourth question will be what is chemical reaction engineering yeah and okay fifth question is what is the information necessary for reactor design okay and last question here is homogeneous and heterogeneous reactions yeah these are the questions I hope you can see my handwriting okay you can understand okay good so these are the questions and the first question when I ask what is chemical engineering can you define now what is chemical engineering and you say few words what is chemical engineering yeah good yeah any other definition you understood now what he says repeat again it is the science that they that involves the processes involved in changing raw material to a given product yeah it is the science he says okay yeah but what the question I am asking is engineering what is chemical engineering so he says it is science it is not wrong it is correct only but any other definitions you know because it deals units operations can you call it is chemical engineering because you know he is right every time different people will tell different definitions for chemical engineering but when you want to explain what is chemical engineering it needs some time for you that means you have to understand what is happening in chemical engineering then only you can tell any other definitions he says unit operations deals with unit operations so that means there are no unit processes there is no process control nothing only unit operations is chemical engineering you see how many things you know we are missing by saying that right but again you are not wrong you are right because everyone is right when they are giving the definition because that is what at this point of time they understand that is chemical engineering yeah any other definition yeah so you see now there is only again that means he does not bother about unit operations he only designs the reactor and that is chemical engineering that is chemical engineering right so like that we do not have a particular definition for chemical engineering all of you are right so at this point of time really you should know you should be able to explain my thumb rule is that always you should be able to explain to your brother or sister which is I mean who is younger to you then if they are able to understand you are able to understand what is chemical engineering that is what is your thumb rule they should not run away the moment you open your mouth right so that is why if you are able to convince them this is what is chemical engineering that is what I mean which means you have to explain in a very very simple words like even Gany what he said is you know he won't understand can you repeat again it is a science deals with dealing with yeah because he does not first of all what is science do we know what is science what is the definition of science okay so this is official definition where official definitions most of the time you don't understand clearly these are only a bunch of words but for that you need lot of information in your mind the information should flow in your blood then only you will try to explain that like for example if I ask you to explain okay that is the definition so what is chemical engineering in simple words the simplest thing which I find is that chemical engineers produce chemicals on very large scale okay this very large scale is very important why chemist also is producing chemicals right so the moment now you know that you are trying to produce on large scale I can give you a very simple examples chemist we have also some chemist here okay you have also done physical chemistry experiments or organic synthesis experiments okay all of us have done in our B Tech days so what do we do if you want to produce a new chemical how much you take in the laboratory milligrams may be 100 milligrams of A one component and another 100 milligrams of other component right so then what you do you put that in the test tube right and then after putting this 100 grams 100 grams then temperature is required for this reaction to take place you go to bunsen burner and then you put there shake it put there shake it why do you shake it if you just put there it won't react why should I mix so all these things without even knowing yourself you do all that okay so at the end how much product they get something may operate also so then you may get you won't they won't get 200 milligrams they may get only 150 milligrams or 160 milligrams okay and then you try to remove that product from there and then try to find out whether you have really that product or not by some other chemical test now just imagine you want to produce one ton of sulfuric acid can you put that in a test tube go and shake it okay so that is where the engineering principles will come right in for example even when you are trying to produce some chemical large scale may be one ton scale 500 grams 500 kg is 500 kg is then you charge these in a batch reactor let us imagine simply batch reactor first right and then it is one ton capacity you don't know how to shake it so that's why you have to put a stirrer that is an engineering problem right so you have to learn principles of engineering where this mixing principles right so this is what what you study in subject yeah mechanical operations are sometimes fluid mechanics fluid mechanics also they have mixing chapters okay so then that information that engineering knowledge will give you how to design a stirrer and there are various kinds of stirrers it is not one kind of stirrer there are so many kinds of stirrers so now you have to see with your experience with your knowledge in that subject and you know what kind of stirrer is the best for this fluid so that means what is that you are trying to do again you are trying to find out what are the physical characteristics of this fluid what you are dealing it is whether it is highly viscous or it is only Newtonian fluid or non-Newtonian fluid means again you will have different you know it is not easy to mix or whether you have solids and you see one reactant may be in solids form another reactant may be in liquid form so then how do you stir this right or it may be one liquid is in gaseous form and another liquid is in liquid so now this liquid will be bubbling yeah the gas will be bubbling through liquid like you have seen no soda or pepsi cola whatever you see that kind of bubbles now you have to stir them okay stirring means again when you have this kind of two different phases like gas and liquid how do you ensure that you have good mixing that is what we do in chemical engineering and these principles or this engineering knowledge is not required for a chemist their job is we cannot blame them because they need not worry about this kind of large scale production at all right their duty is whether a new reaction they can find or not which will be useful for the society for the humans either may be in terms of medicines or it may be in terms of some intermediate for this medicine or it may be some paint or it may be some other you know some acid or it may be benzene or toluene some other new component where it will be useful or some plastic component before that you know that a chemical reaction should take place so this is what is you know that engineering principles right so that is why when you talk about chemical engineering what you do is that on large scale you have to use always engineering principles because we are dealing with chemicals it is called chemical engineering right so now other thing which I want to tell is that you have only talked about mixing right what about heat transfer because now you have taken this test tube put in the Bunsen burner and then you know exposed that for temperature because the diameter of the tube is very very small heat is uniformly distributed so by shaking even inside that liquid also will have uniform distribution so there is a possibility for the reaction to take place throughout that small volume uniformly so that is why you are shaking there right but that we cannot do on one ton scale so what I have to do now stirrer we put but how do I supply heat right it may not be supply heat sometimes you have to remove heat because if it is highly exothermic reaction you do not want that kind of heat to be generated because you know it may catch fire or it may spoil the product so that is why you have to control the temperature that means you have to remove heat what do you do yeah you cooling jackets again many questions will come where do you put this cooling jackets directly inside the reactor or outside why outside why not inside so all these things are chemical engineering subjects these all form engineering subjects but when you talk about that chemical reaction alone how your molecule is going to attack another molecule and then the collision of these two molecules will give the product that is the science he is not bothered about how it is removed at all at that time when a molecule is coming and eating another molecule and that energetic collisions will give you the products all that theories we have right so for all that you need not use any engineering principles there only thing is one molecule you visualize another molecule will come collide and then the resulting collisions some energetic collisions will give the product so now he has to interpret okay when so many molecules are coming and colliding how do I find out what is the rate of reaction because finally so many molecules are colliding so much product is formed so now what is the formation of product rate of formation similarly the opposite part of that is what is the rate of reaction because when the rate of reaction is happening only production is happening right so that is why that is why you have you know leon spiel great word is minus r a okay you only popularized that minus r a for us minus r a means rate of reaction for the reactants right so products normally we never use so but that is the sign spot for us okay so that is why chemical engineering one of the simplest definitions is that chemical engineers produce chemicals on very large scale that large scale is nothing but chemical engineering why for example I told you heat transfer you read in chemical engineering and mixing you read in chemical engineering and when I also have the batch system so I told you this mixing also come in fluid mechanics that means fluid is moving and also after completing your reaction you have to discharge that products and then you have to send it to some other maybe distillation column to separate again if the unreacted reactant and product so that means that is the mass transfer equipment that also sometimes they do chemistry do right how do they do that they also have very small distillation column it is single stage only one baker and then just heat it and the vapor will come condense in a simple condenser and then they get the product but imagine that to be done on a very large scale with you know hundreds of tons per day what kind of big size of condensers you require that is why we went to distillation which is a wonderful operation right so all these things in a fluid flow automatically comes mass transfer distillation is mass transfer operation because you are separating two that means you are making two components move separately okay mass is moving from one place to the other place right so from liquid to the vapor and then you condense and again take it that is what is mass transfer so now if you want to control the reaction temperature automatically controls will come so now you see you know fluid mechanics automatically coming mass transfer automatically coming control automatically coming and you know material and energy balance comes much before that because you know how how much you have to put in the reactor how much will come out depending on the conversion so all these things all subjects are covered now right so chemical engineering is is the field where you produce chemicals on large scale you try to explain this to your brother or sister they will happily understand that you are giving examples now so because we are we have to produce very large amounts so we cannot take small equipment and then shake it and then take the product so we have to I mean mix thoroughly and you can also tell that you know mother is mixing in the kitchen with you know some kind of spoon okay or you have that big spoon and all that so with that she will also stir when she is cooking sambar again uniform right so even I think that kind of big spoons also not possible so that is why we have to go for real stirrers with different shapes and sizes so that is what what we read in chemical engineering then he understands okay so that is why starting point is chemical chemical reaction engineering chemical reactions and then automatically all subjects will form they have to support this particular reaction that is why always I have that dream I told I will think my earlier students also this dream is to have flow chart with only reactor that is the minimum flow chart that you can have if I have a reactor I designed a reactor where the reaction is taking place at room temperature okay because many biochemical reactions are taking place at room temperature there is 100 percent conversion okay now I also have pure reactants what do I need and also 100 percent conversion pure reactants will go to pure products so directly you can send the products to supermarkets only thing is fluid flow you should have pipes or you should have some conveyor belts where you can just directly send to supermarkets so that is what is a beautiful subject for chemical technology where you do not have to remember any other equipment now we know what is the what the hell you had when you are preparing for chemical technology examination how many flow charts you have to remember right so I know most of you would have remember I also did the same thing right so all of us try to remember only as much as possible after the examination once needs everything will come out forget so tomorrow you do not know what you have written yesterday in that examination so that will be beautiful now if you are able to design this dream flow chart that is my dream okay we cannot we have only this kind of reactions if possible unfortunately they are not possible we do not know after 100 years 200 years it may be possible right so that is why that flow chart you will have for each and every chemical where you have heat transfer equipment heat transfer you have to study mass transfer equipment mass transfer you have to study flow you will have and also you know storage vessels you will have so all that learning is chemical engineering we do not have to tell you a particular definition I told you definitions will be always difficult to remember anyway I am going to tell you the official definition okay you have to note down and then keep it with you but the simplest one is that okay and I have we have forgotten one very important subject I have not told you till now what is that thermodynamics where does that come yeah actually thermodynamics is the god says possible not possible not possible means you cannot do anything possible means you can do something yeah okay reactions plus anything else equilibrium diagram yeah where do you think where do you sorry thermodynamics will tell you how much percent is combustion that is kentics how far the reaction that is how fast thermodynamics cannot it is only kentics initial and the first state the initial and the last state can be said by thermodynamics yeah I mean okay reaction we say that you know it is feasible or not that is that is that is information you get but how fast means only you have to go to kentics that is what is the reaction engineering okay that is why it is science because when you are looking at molecular level it is science when you are looking at bulk level that means okay forget about molecules I will put my maybe you know to study the kinetics maybe one kg of one material another kg of another material now there are millions and billions of molecules in that I do not worry how they are reacting but after waiting for 10 minutes I will see the product so that means you are now looking macroscopically in the system and then try to find out at the end at the end means maybe you know every when you want to find out a concentration with respect to time so every time maybe five minutes five minutes five minutes five minutes you try to check whether reaction is happening or not that is what is again reaction engineering you are not really talking about science there science is that going into the molecules and then try to find out okay in what way in what angle this molecule is going and colliding another angle I mean another molecule only some angles may result into product and then you try to because all of us are ambitious we want to produce as much as possible so we would like to send all the molecules in that only that orientation where you get maximum product okay that is scientific theory I know experiments also they can do and then they can prove that right so this is what is the one of the simplest definitions of chemical engineering where you simply say that okay we produce anything any chemical on very very large scales that large also is really large if you go to ammonia production where they use for fertilizers and all that the plants may be 10,000 tons per day 10,000 tons per day 10,000 into another 1000 kgs per day 24 hours you have to produce that like that even sulphuric acid you know that bulk chemicals where large amounts you produce and the beauty there is you go to that large scale and also you produce maybe 1 kg 2 kg very costly medicines you cannot produce more than that okay for example in biochemical engineering particularly extraction of some chemicals from you know kidney liver and all that you know we also do that in biochemical engineering biochemical engineering is no way different than chemical engineering okay so that is what is the simplest definition you remember this what I explained right what is that you are trying to do in chemical engineering and if someone ask this is the problem I think even now many people in even in IIT Madras some I think I stayed here almost 30, 32 years even now some of my letters will go to chemistry department that means people do not know the difference between chemistry and chemical engineering okay but it is very good and my another thing which I started saying last 4, 5 years suddenly that idea came to me is chemical engineering starts when chemistry stops very nice no repeat what I said chemistry stops where does the where do they stop small scale small scale that is all I think that is very simplest one to remember again I told also in one of the conferences as I mean this is inauguration for chemistry conference I told that I mean we are cousin brothers but you go to till certain place afterwards we continue the journey so then I said I first told this sentence you know chemical engineering starts when chemistry stops that is one of the simplest definitions also which you can give then you can explain what do you mean by that right because many people do not know I think only you know you should know then only you should tell otherwise otherwise if they ask okay tell then you may not know right so this is what most of the time it is happening to you in interviews only for your happiness or for some great effect use very difficult term okay nanotechnology use then when I ask okay tell me what is nanotechnology that is all I think you know only nanotechnology you cannot so nanotechnology nanotechnology because you do not know you do not have even one example where this nanotechnology really works okay I mean nature has started already nanotechnology right I think big bang theory you know all fundamental particles and that build up slowly whatever shape it wanted of course that is by nature it has done it but humanly we want to do the same thing that is what is nanotechnology right till now the molecules the way they are combining you allowed them to combine but now we do not want to allow them the way they want to combine we want to have our own type of you know the products that is why I think you know this I have been telling also some of our friends are here already taken this course and you know I tell this example always I was in Malaysia for 2 years teaching and I was teaching CRE course and then I asked how do you produce sulfuric acid so I asked I think in Malaysia you know we think that there is a Muslim country no freedom for ladies by God they have tremendous freedom in fact in our country our ladies do not have that much freedom if I look at any time on the roads more than 50 percent of the drivers you know their own vehicles or ladies and any office you go more than 50 percent are girls okay in the class in my class 60 percent were girls in chemical engineering so normally chemical engineering we may not get many I think you know electronics they may get many or in sciences our people get so like that you know there are many girls and one girl I asked okay please tell me what is how do you produce she says no problems are I think very very easy you take H2 you take yes and you take O4 put them in one place you will get HDSO4 you know really all the people love like this only I told no I think she is terminator 10 not 1 2 3 because all terminators come from our future so she has come from your future because she is now imagining that future knowledge where after may be 100 years we may be doing the same thing that is what you are supposed to do in nanotechnology you have to control the products the way you want how do you start you have to start from molecules the nature does that how our body is formed you know I mean at the level of you know that sperm and egg level where is the shape there is no shape there no we I mean the sperm has separated shape and egg has its own shape but by combining those two and then the DNA information in may be one month you will have one shape it is not true only for humans I think for all life you know all the mammals after two months it you have different shape and at the end of ninth month we are here okay the shape will not change I think only slightly it may change till 19th year or 18th year teens okay so you see that is nanotechnology it is building up from the molecules because now we want to control that at molecular level you need lot of sophistication for doing this why molecules you cannot see you have to catch one molecule H2 and then catch another S2 S and then put them together and then bring O4 join together and then give the H2 SO4 in fact we may reach you know we do not know after 200 300 years later that may be what what we are doing if you go to doctor at that time he will just call you okay this is the disease you have so this is the medicine he may pull out all these molecules benzene toluene and all that together no really it may happen it is really beautiful that is why life is so beautiful if you imagine all these possibilities and we came to this level because of our imagination only this level we have reached because of our imagination we are able to fly very happily in sky with that big flights where we have you know that particularly airbus 800 or something is there where my god it is like this building I say more than this building size wise how beautifully it is flying how did you get this we got that because we have observed birds fly and you felt sorry that and I do not have wings to fly okay and then even people tried that they had wings you know that condor man or something they call so they jump from buildings broken their legs and all that so many many people tried that okay it is their sacrifice what happily afterwards I think who are the people right right brothers yeah right brothers it seems they used to go to these birds wherever they have in the water they used to simply observe it seems how the birds are taking off when they are flying and when they land how they land okay catching fish and all that they do not bother okay but only flying and then landing only our birds can know they are flying and then also landing there only to catch fish so that they can eat and then you know survive that is their food but we are not doing that we want to fly how beautifully it is now rackets and most wonderful thing is my god billions of miles away someone takes the photograph that comes to earth with a beautiful picture what kind of you know our medicines how many lives are saved you know because of our medicines produced by you know pharmacists and chemical engineers and biochemists how many I think you know and chemical engineers saved the world I do not know whether you know this or not because at one point of time particularly Haber process for ammonia and why he was so much interested in having this ammonia process finally to be used as fertilizers only for that okay at that time population is increasing but fertilize I mean the the growth without any additional fertilizer the growth of food is not that much production of food so that is why at one point of time chemical engineers really saved by producing large amounts of fertilizers where the productivity increased five times ten times with the same land area is same but from the same land because of putting these fertilizers then they got more and more you know all the whatever they produce wheat or whatever right so that is all fruits vegetables all that they could produce that is why I think we also contributed for saving the world and also another saving the world is penicillin penicillin invention is one of the greatest you know stories for chemical engineers also for bio chemists chemical engineers and even doctors all these three people together they worked and then finally they could produce during second world war penicillin and then that penicillin saved many many lives many families were happy otherwise I think you know many people would have would have been without fathers in that family right because at that time only only men were fighting women were only at home right so that saved lot of lives so like that the chemical engineering contributions just by learning thermodynamics heat transfer mass transfer fluid mechanics that is all that is again one of the beautiest parts which I like in chemical engineering any chemical you bring in the world only five subjects correct no what are the five subjects of course reaction engineering is one mass transfer heat transfer and momentum transfer if you combine all these three as transport phenomena that also will become only one subject right and then of course material and energy balance of thermodynamics thermodynamics will tell you whether what is possible what is not possible right so that is why now onwards please try to explain you know you catch some of you see here you may be happily enjoying and then you know you thought that you have understood but the moment again you cross the door you may forget that is why you have to repeat yourself that is why in your room you repeat what you have learnt here just sit down and then try to because we don't tell many things you know this entire class I have just told you what is chemical engineering only one point to make that one point we give so many examples that is all in every class there will be only one point or two points the moment you go home you just note down that point and the explanation and all that you catch someone you catch some computer science guy in your room in your hostel okay and then take him for tea and then start telling this okay girls also right yeah so till he gets bored because you know he cannot immediately run away because you bought him tea so I think that is the tea is over he will be there with you so till that time I think you can tell that you know it is only whether he listens or not don't worry because most of us are like that we sit here our mind can go somewhere right that is what I that is why I told you I like matrix movie because of that because you sit in the chair put that rod here you go anywhere you know right so that is why all of you should see that movie right that matrix so that is what because that is what what we do he has shown that in a beautiful way in that movie all the time we do that right now you may be listening to me but your mind would have been thinking okay may be thinking next class may be thinking for those people who do not have next class they may be thinking food you know so many things in your mind right so that is why I think this one chemical engineering itself if you are now tied to tell or you discuss on your own with your friends all chemical engineers together then you will not forget otherwise if you simply go out of this room and then okay let me see when the when it comes to examination or not so most of the time you know we postpone till examination right so if you are trying to do that you will not learn much I tell you in any class you will not have more than one or two concepts in every point not even concepts okay I think I will stop here and yeah this is what is the first question entire semester I can talk about these four questions