Fouling in Heat Exchangers - Part 3





Welcome friends, we were discussing fouling in heat exchangers, in our course heat exchanger fundamentals and design analysis, fouling in heat exchangers and as it is there in all the title slides, most of the material I have taken from the very comprehensive book on heat exchangers by Sah and Seculis. There are other information but this book has collected information from many other source books so I had taken from this book and but only a small portion what is there living in this book has been projected in this lecture so this reference I have given it has got to pass first thing is that first thing is that I like to acknowledge and second thing I like to eat this reference to persons who are interested in doing some more information regarding housing to the straight-forward to get some more information for that they can get the reference is giving it back to show further informationNepali show all the hiring process now we know bye-bye this time we know that how he is not going to be avoided control removed whatever you say before foundation or control removal and cleaning fee online offline let me spend some time with all that means we end this is a very good strategy for many of the cases that if we can professors for tell if we can prevent I mean if we if we become healthy and if we afford not falling see that is the best way but are you cannot avoid sickness he was not well in spite of you good care of it then you have to take sometimeswhat is the configuration of the heat exchanger same size exactly next is the heat exchanger breaking it can be done by 10 in the operating condition of the exchange it can be done by some other things let's say in sound system I I install Sutton field so certain particulates when there is a circulating fluid particle are getting caught in the field or let's say that I have got some hvac system air conditioning system I have to take outside and outside their their to be dust particle that truck so I got a fit so obviously I take care of certain amount ofcleaning house removal and cleaning could be done that depends on many many things that how critical is better texting so then depending on that I have to take mine clinics bracket whether it is a whether it is a liquid asset exchange or gas to liquid heat exchangers kind of what kind of design it is so if it is a cell intuitive stay here then obviously we have got some sort of cleaning strategy let’s say that one said he could be that without being in the same side clean the tube services etc and that you can have some water jet or kind of kind ofwhat them gaskets space died in the frame and again in many industries industries and sometimes every day because the product we have to get it is it is sort of a product is depend on on the size of the text but let's say I have got a microSD simply it can be put in a furnace and temperature can be controlled at high temperature of body temperature can be gone through which is called baking and we can get rid of most of the violence which are deposited on the surface but a large heat exchanger in that way we cannot put it and different ways of online and offline online andsome people called is also an online cleaning of the day and some people are missing in defining it online cleaning me it will not affect the performance of reply reply to Elan as it is and heat exchanger is to be paid if you will give you I will not have opportunity to discuss all sucks but they're ready for installmentor.com holy biocides dispersants biostats 455 so different type of powder and water now you see sometimes the situation is tricky I have already mentioned in one of the ideal that that cooling tower and big water what is a condenser and another is a cooling tower there will be political fountain Valleybreathing biological fouling what can what one can give some sort of a closing etc one that will prevent the building but most of that will have a detrimental effect on the tubes of the cottage so you see one has to strike a balance and mitigation of power or control of Audi is not that not that easy job because many cases they ordered differently if you want to surprise you one day on another mechanism assisted by one has to be judicial one has to take proper precaution I didn’t some cases some sort of optimisation is to be some sort of optimum strategy is to be taken modificationmonitoring modification and replacement of devices water production and recirculation strategies are the life process adjustment physical devices for cleaning like single SpongeBob 3D the use of reversing the flow circle process this is what I have told that you have gone brass let’s a nylon grass and in the circulation system these glasses are also moving from one part 1 one end to another end and while they’re moving they’re not allowing any position of the sun okwhich mean of monthly data transfer at the same time when they are moving components some sort of delay nextvarious alternative devices and methods like magnetic field radio-frequency ultra ultra violet and acoustic radiation electric pulses and surface treatment for diabetes and these are all different methods the most frequently used techniques for preventing water cycling is a conventional water treatment so we had water treatment we give treated water sometimes deionized water sometimes water with some chemical additive to the circuit so that we reduce the water cyclone house as water is in many cases one of the main main constituent of the liquid stream so that’s why the discussion is due to some extent bias towards what it does not mean that there cannot be other kind of liquids there are other kind of water is recommended to eat and that’s why he has been good and water treatment is a very common practice in large industry so that housing can be kept to the minimumtransfer mitigation techniques can be applied either on or offline online techniques used for application include various mechanics floor scrubber is mechanical vibration on the outside of the new chemical free flow reversal it to write the best way to clean the surface so that the transfer application are you sleeping so this is a breaking is also done sometimes what happened that frosting is very common in Liverpool return of the operator of a of an air conditioning system and in that there should be heater inserts and with this inserted heater time to time eating and that that can melt the ice and heat packs applying cleaning with water and baking products and their information combination of methods and a golden rule is that the cleaning schedule that deposit clear are not so heavy or should I do that The separation or removal of the people becomes a very formidable and our removal of the deposit Claire’s becomes a very formidable jobif you put that we provide that we give that is one thing another that had it is for the gas a fluid surface cleaning technique obviously service training techniques ultimate give it to her then I just think design up Cross to minimise out so that is always a good practice control of gas or liquid side howling should be attempted before any cleaning method is trial be found in control procedure should be preceded by verification of the existing house so what kind of holding is taking place that has to be that has to be accessed and then only some sort of housing control procedure is to be adopted identification of the features that dominates the filing of accumulation so first thing what kind of outlets are generated first point second point is that that house is Poland points at home or gets deposited characterization of the deposit so you see whatever we have discussed if really one has to take care of the department of the plant that has to be very careful and that has to be a good kind of analysis that what is the chemical composition of physically what is happening so then only one can have a good strategy of housing controls and same heat exchanger can be used for different applications so I get to get it exchanged can be used for different purposes in one case it is using flogas in another case it is using from different sources ok this part one has to be carefulthe medication of the following can be prevented if the surface temperature is above the freezing of the paper from the accessories for unification can be minimised by creeping higher velocity of these places having some pretty interesting so if there are impurities in the district sometimes the freaking there are certain constituencies product of combustionminimising the lead content in gasoline or unburned hydrocarbons in diesel fuel so you can understand why the suspect or reducing the fuel-air ratio thereby minimising the floor impact min floor cross section three to four times more than the maximumincreasing or decreasing the velocity of the gases 3 depending on the application sometimes we have to buy increasing velocity and sometimes that's goodI think it's some sort of action and reaction maybe just maybe on the solid surfaces and that gives a petition filing the petition evolution which we will discuss that is what we have to do replacing the call with fuel oil and natural gas more pollution pollution that is one thing but it gives most housing tenancy of housing is much more in common because they are articulate their way of a full of people who may not be there because nobody is nobodymaintaining the exhaust gas temperature above the dew point she have a appointment at the temperature at then there will not be any kind of formation of acidic deposits and then waiting your selection is very important that means stainless steel glass plastic and silicon are registered to room temperature can do if we have low temperature at location we have to select this kind of material that is less than 260 degree celsius to 60 degree to 815 degrees Celsius superalloy to super alloy and stainless steel can be used in this range at superalloy and ceramic can be used for high-temperature application by at the temperature is higher than 856 some sort of strategy by which we can avoid now that we are going to call Roshan call sending me texts to destruction of exchanging is on the materials from the heat exchanger surface is coming out that can get people to do and create dependingsurface temperature and working condition decoration without filing it is complex signature and also a truck there is a very interesting figure you can see that what are the different factors influencing Carlson environmental factors that their material factors and stress factor  environment and material are interacting there is no stress factor this is the doorwhat treatments are responsible for explaining this figure each and every item so you can go through it and you can understand what has been told and what are the this is almost ceramic self-explanatory that maybe real includes material factors include compositions alloying elements treatment effect of fabrication microstructure surface condition passivity tendency for foggy all these things and semiconductors and their now go to the next line should calldo you have difference in between there is an electrolyte so response from shoprite and then there is pitting corrosion local autocatalytic caution and there may be material or so you can see the service has become very horny uniform call Roshan theoretically at least there will be uniform loss of material from which places because it has taken place so we can see if it’s or small holes or things like that registration is very much related to stress balls accessible straight straight yudelson you can understand that somebody really getting loaded it could be caused by depositiononly one component is reacting chemically and getting removed from the space so then we will have material with different competition making competition with baby that initially what competition was there and finally after because of the shop here this is not good weakness I come to an end that very quickly I have told you regarding falling and then I am told certain things regarding corruption which is also one kind of detrimental effect which we can see in heat exchanger and we have to avoid this thing some of the strategies I have told particularly regarding housing I have told some of the strategies for corruption also there are subtle strategy what one can I have given the reference please go to the reference you will have some idea how corrosion can also be tackled that book will have cross references if somebody is more interested then they can go through the cross references. Thank you for your attention.