00:00like the lightest dense phase or for the calculation so this is the calculation only
00:05so 3 feet per minute it should be either 6 inch plus 0.5 of this density you will get
00:12the volumetric
00:13flow rate and because we are using the strokes law welcome to the channel today we are discussing
00:20the three phase separator part 2 so let's start in three phase separator part 1 we have completed
00:28the step 1 for calculating the diameter based on the residence time and we got the diameter as d is
00:34equal to 1.73 meter and for step 2 also we have completed which is that calculating the diameter
00:40based on the separation of the vapor phase from the continuous liquid phase so you can just go
00:45and watch that videos before starting these videos because most of the step 3 e 3 and 4 is similar
00:51to
00:51the step 2 only so it will be easy to understand so step 3 calculation the diameter based on the
01:00settling of a liquid from vapor phase if you see in our earlier lecture when in the basis of separator
01:06we have discussed about the intermediate law in that we said that intermediate law is used for
01:11liquid separation from the continuous vapor phase so we will use the intermediate law
01:19and because there is a three phase in our problem so we have to consider the least dense phase or
01:26lighter phase for the because it will get separated slowest so we have to because we have two liquid
01:33phases so we will take the lightest dense phase or for the calculation so this is the
01:38intermediate law for calculating the terminal velocity
01:43velocity where dpl is the particle diameter role is the liquid phase density light phase
01:51this one this is vapor phase density this is vapor phase viscosity this is vapor phase
01:59again the density and this is g is your constant gravitational acceleration constant
02:06so when we solve this we can get the terminal velocity
02:13so it is similar to the vapor from liquid case and this we have to consider the our center line
02:22just
02:22above the normal liquid level and particle has to or liquid particle has to fall from the top to the
02:28liquid level which is the x distance so liquid has to come down from the continuous vapor phase
02:37and to get the continuous phase velocity we have to consider this section as a z which is the cross
02:45sectional area for
02:47for for for the arc or the chord of this circular section which is the height of x distance so
02:55you will
02:55you will get the similarly uh the velocity uh the velocity uh the velocity is equal to q by cross
03:02sectional area
03:04section into z of d means this is z is the this uh section of your total cross sectional area
03:11this is the
03:130.785 into d square is the total cross section area and we have taken only the z because the
03:19vapors are
03:19flowing from this cross sectional area only so we can get this way the continuous phase uh velocity
03:29so vc is the horizontal or continuous phase velocity
03:32qv is the vapor flow rate and 0.7 dz is the cross sectional area of this complete vessel
03:38but into the z is your the required cross sectional area for the vapor to flow
03:44so similarly uh what we discussed in the vapor to liquid separation if the liquid particles falls from
03:53x distance in the time required to fall that x distance is t which is similar to the liquid or
04:00the vapors goes from inlet to outlet the time required is same then we can say again the t is
04:10equal to
04:10xd by vdl which is your terminal velocity which is calculated by the intermediate law
04:17and yd by vcv which is your continuous phase velocity to require travel this y distance
04:25so now when we replace or we'll add this vdl formula and vca formula here
04:31we can get the equation to find out the d
04:39so similar to the step 2 we can get that xd by vdl so we'll get we'll replace this uh
04:47continuous phase
04:47velocity here and the terminal velocity here then we can get that d is equal to this formula
04:55and uh we know x is 0.25 y is 2 uh z is 0.2 and y is 2
05:02and uh particle size is 250 microns for the
05:06liquid phase which we already uh discussed in our uh introduction lecture where we have mentioned that
05:14the liquid and vapor separation uh we have to consider the uh particle size if we don't know we have
05:20to
05:20consider 250 microns so accordingly we are considering that and this is our problem statement
05:25so uh we have to get the continuous velocity for the vapor so flow rate is this
05:31this is a kg per hour flow rate so we have to convert into the volumetric flow rate and all
05:38this
05:38information already available here i have solved this problem in the next slide a step by step method
05:43is also given so when you solve this d square you will get d as a 0.25 a 0
05:51.215 meter
05:55so this way we can calculate the diameter for the liquid particle separation from the continuous vapor
06:01phase so how we got the 0.2 i have given the step by step equation so this is our
06:08problem statement
06:09then in the solution first get the volumetric flow rate change so this is a uh this is your mass
06:15flow
06:15rate divided by this density you will get the volumetric flow rate then second step get the total
06:22liquid flow and make it into meter cube per second so meter cube per second means just divide it by
06:283600 so which i did here you can find it out and this is your basis it will be used
06:34for the all the cases
06:35so i have converted for liquid as well as all three and kept it ready here then you have to
06:41just put
06:42all the variables like x is 0.25 z is 0.2 y is point uh y is 2 g
06:49is constant 9.81 meter unit also has to be
06:52very uh correctly you have to put particle size is 250 microns so convert it into meter because all other
06:58are in meter then q u already q v is we can get from here so this number i have
07:04entered here density of
07:06liquid phase is available here the lighter phase or lightest phase and the density of your uh vapor phase
07:14which is this two and viscosity is also mentioned for the vapor phase and then just put this all
07:24here you can i have solved the first top numerator and then denominator and then we can got the d
07:30d
07:31square value and when you solve for the take a square root of it it comes 0.21 335 meter
07:37so this
07:38way we can solve easily you can make your own excel sheet
07:44tip 4 is to calculate the diameter based on the settling the liquid or you can say heavy liquid from
07:51the
07:52lighter phase liquid lighter phase continuous phase so calculating diameter by settling velocity liquid
08:00from the lighter liquid is exactly same as the calculating the diameter for the settling vapor
08:05from the liquid phase so it is exactly same as the step 2 and because we are using the stroke's
08:12law
08:12because if you seen in our lecture we have mentioned that dispersed liquid separation from the continuous
08:17liquid phase we use the stroke's law so same stroke's law we use which we have used in the step
08:232 it is
08:23exactly similar to the step 2 only you have to uh you will find that uh the for the heavy
08:31liquid it is
08:32mentioned heavy liquid and lighter liquid so that only the uh demarcation is provided because here in uh vapor 2
08:41liquid or step 2 it is liquid and it is a gas here so just formula has uh denomination has
08:48changed
08:50so where dph is your heavy particle uh liquid particle diameter
08:56and these are the your densities viscosity velocity for the dispersive phase and g is your gravitational
09:04constant so it is exactly step 4 is exactly same as step 2 if you understand step 2 it is
09:10very easy to
09:10understand step 2 3 and 4 exactly same we are settling our heavy liquid particle from this
09:18low liquid level to the bottom it has to come which is has to travel x distance
09:23and suppose so and this is your cross-sectional area where we have to have a continuous phase liquid so
09:30we have to calculate your continuous phase uh velocity which is flow rate divided by cross-sectional
09:37area and this is the section of z again the same as what we discuss in step 2
09:45and this is inlet and outlet so the time required for inlet fluid goes from inlet to outlet or every
09:51particle liquid from inlet to outlet is t which is similar to uh particle has to settle from this part
10:00from the top of the liquid level to the bottom of the liquid level which is has to be x
10:04distance if
10:05this is also t then similarly we can say that the t is equal to xd by vhl and vd
10:13by tl so this is your
10:15terminal velocity and this is your cross-sectional velocity so when you replace this in this formula
10:23you will get this section and from this we can find out your this d square
10:32similar to that we will uh will get x and z values and this is our problem so when we
10:40solve for the d
10:41square with the particle size of 125 micron which is come based on the our earlier lecture also we have
10:48explained that when liquid from continuous uh dispersed liquid phase from the continuous liquid phase we have
10:54to consider the uh particle size as 125 micron so we followed the same and when we solve it for
11:00the uh d
11:03we will get d as a 1.2 or 28 meter in the next slide i have described how to
11:09uh how we are getting this 1.25
11:12in detail
11:16so this section remains same
11:26so if you want this excel sheet you can just comment uh on this i will share or comment your
11:48email id i can
11:49share that so this way we got the diameter for all the four steps and this is just rounded up
11:59to the
12:00next 100 mm so that's why this number is little bit different and now we'll see for the step 5
12:05if you
12:06have a coalescing banquet how to calculate the diameter for this step this is the last uh step in the
12:13calculation of the diameter then straight away you can go by l by d and get your length
12:20so step 5 calculating the diameter for the coalescing blanket this is very easy just you have to follow
12:26one step the coalescing blanket design based on the velocity of 3 feet per minute this is the very
12:32important part in this calculation only so 3 feet per minute it comes out to be 0.0125 meter per
12:39second
12:39because we are calculating in meter per second so i just converted it in but to remember because this
12:44number is not easy to remember so 3 feet per minute is easy to remember so uh this is just
12:52we have to
12:53do we have to calculate based on the continuous phase velocity like velocity is equal to flow rate
12:57divided by cross sectional area so as you know z is 0.2 and vtl is your continuous phase velocity
13:07q is
13:07your flow rate liquid flow rate and 0.7 it's it's cross sectional area so when you solve uh so
13:16what d
13:17square what we have to do because we have calculated the d for all four steps so highest d is
13:221.8 so i have
13:24taken this d and then i um because coalescing blanket uh or coalescing design is the one case uh
13:32one design condition is that you should have a velocity of three point of three feet per minute
13:38so i have to check what are the diameter highest diameter came in my result if this is suitable for
13:44this three uh feet per minute then i need to go for any other diameter or if it is come
13:51slower than
13:51this then i will go for this highest diameter only so that's why i taken this 1.8 as here
13:58and i have solved it so when we solved it it comes velocity came is out to be 0.0201
14:06meter per second
14:07so this velocity is more than 3 feet uh 3 feet per minute or you can say 0.152 minute
14:14per second
14:14so it means this whatever the diameter we have selected is not correct it is required a bigger
14:21diameter to maintain this velocity so what we will do we'll solve this again considering this as a
14:27velocity now so in this formula we'll keep our velocity as a constant like 0.152 and then when we
14:36solve it for the d square then you will get the diameter as 2.1 so this is the more
14:45than your
14:46earlier calculated diameter so then this may be your governing diameter
14:51based on the coalescing uh velocity because this velocity has to be maintained in the your separator for
15:01the half a coalescing to be happen so that's why d is coming higher
15:08so here also i have given the step by step calculation you can just go through it
15:14it's a very simple calculation two step calculation first we have to consider the diameter
15:19and calculate the velocity and second because we are uh diameter is coming or you can say velocity comes
15:26higher so uh we are calculating for the reverse diameter
15:35okay so based on the step uh 125 we have got the largest diameter as 2.1 so uh we
15:45can say that this
15:46is our governing case step 5 and we can calculate the lyd ratio based on the lyd is 3 so
15:54l can come as a
15:576.3 meter
16:02so this way we can calculate the diameters for the three-phase separators now mist eliminator because i
16:08have not covered here because mist eliminator required and on initial basics for uh mist eliminator and then
16:14design of it so that will do separately and inlet and outlet distributor also will do separately
16:22if someone is difficult to imagine how the separation is happen so this is one picture i have found on
16:27the
16:27internet which it shows better representation where we can imagine how the separation happens so this
16:35is the momentum transfer then this is uh liquid is following from the continuous vapor phase and here
16:44from the continuous liquid phase vapors are going up and this uh from this uh continuous or heavy liquid
16:53is falling down from the continuous uh lighter liquid phase here maybe there is a baffle so this
17:00is just a representation i found good picture so i just shared it
17:06so one major uh part in the horizontal separated design is where the positions of nozzles will be there
17:13and how the boot uh levels and where the boot should be installed so the inlet nozzle should be
17:22basically from the tan it should be either six inch plus 0.5 of your inlet flange or your inlet
17:30pipe
17:30diameter or it should be maximum 0.5 d so d is your diameter of the vessel so it should
17:36not be more than
17:37uh 0.5 d uh 0.5 d similarly for the outlet also outlet nozzle should be maximum 0.5
17:46d away from your uh tan length
17:51and your uh this boot should be also the 0.5 d from your tan length your skirt support is
17:59is d by 4 maximum
18:02and this length of your foot because boot uh design will see separately this should be around
18:093.5 feet maximum so these are some uh basic for the horizontal separator
18:18this has to be processing it has to describe in their uh process data sheet
18:26this is also the uh description of step one where we are calculated the diameter based on the
18:32residence time so how to calculate it is given step by step here so you can just go through it
18:37if you
18:38want an excel sheet you can just uh put it in the comment your email id i will share it
18:46this slide shows just the step two calculations which we have done which is not covered in the last
18:52session or last lecture four because there is a lot of other disc um important part points are there so
19:00to solve the d we have given the step by step calculation here so you can just go through it
19:06and you can
19:07uh find it easy to calculate that so how we got the d as a 0.5 there
19:15so after this we'll cover the drop leg or boot sizing for the three page separator then we'll do
19:20one example for vertical separator then we'll discuss about the inlet distributor
19:26mist eliminator design and then finally last we'll do a problem with the api 12g and gpsa method so you
19:35can compare that which one is the better for the use thank you for watching the video
19:42thank you very much if you have any question you can write to us or comment on the comment box
19:48or
19:48you can also reach on to us at conceptengineering2025gmail.com link of the sessions uh all the
19:56sessions we completed till it is module one pressure relief valve module two heat exchangers and
20:01model three separators are going on so links for all this um available in description box you can go
20:07through it thank you
20:09you
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