oil flow rate??

[MilanMhatre]

We have thermic fluid heater of 1,00,000 kcal/hr capacity. Which is use for batch reactor to rise temperature.
when reaction is over at temp 230C then heated oil start flowing through HE which cool down reduce oil temp upto 70C.

from above case i have to ask " Flow rate of oil pump and flow rate of oil which coming out of reactor is same " ??

What is the oil flow rate ... ??
or how much cooling water required to achieve 70C temp??

Data-

3 H.P pump
0.75" dia of outlet pipe
15m Head
at temp 230C

 

[cloa]

I have some idea of what you have written but its not clear. Read my tagline.
The Thermic fluid heater heats some process fluid in batches? and the vessels temperature is regulated by oil? This oil itself is cooled by water in a Heat Exchanger?
The mass flow of the oil except for leaks and transient conditions (I suspect the oil is continuously flowing) is going to be the same in and out of the fluid heater. Its flow rate is not going to be the same if it has different temperatures- your piping must allow for that. If the oil comes in at a low temperature and then out at about a max 230C (which is unlikely it going to be less) then its going be much less dense so its volumetric flow rate is going have to be greater.

Once you have the real oil outlet temperature and actual mass flow then its just a standard heat exchanger problem.

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[LittleInch]

I read this slightly differently in that the heater heats the oil which is then used in the remote batch process. After the end of the batch the op wants to cool his oil down to 70c.

Flow rate of oil will be different in and out of the heater due to thermal expansion of oil, but not more than 10 to 15%.

Oil flow rate will be whatever it needs to be to transport the heat from the heater to your process if I've got that right.

How much cooling water depends on mass of oil in the system, it's thermal capacity, how long you want it to take to reduce temperature and inlet and outlet temps of the water. Assuming you don't want the water to boil then you will initially need much more water flow than the oil, say four times at least, but maybe much more if you have a max water discharge temperature.

Far too many unknowns for anyone to give you an answer.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[MilanMhatre]

@LittleInch: Thank u for ur kind reply.

I have very simple problem of Heat exchange but due to insufficient info at my work place i wouldn't find result.

I know the formulas etc but dint know the flow rate etc(for oil circulation we use 3 HP pump , 0.75" dia pipe, 10m Head).

Problem: 1) Basically we have to cool down BATCH process.
2) I have to cool down my oil temp from 230C to 70C,
so which type of HE and how much water( cooling tower inlet temp 27C) flow required for that??

 

[LittleInch]

The pump data sheet or plate on the pump should tell you. My best guess is a flow rate of around 30 to 40 m3/hr.

As i said to stop it boiling you probably need between 5 and 10 times as much water as the oil flow rate into a shell and tube heat exchanger, but I'm not a detail HE person.

There's still not enough info here to give you anything much better than that.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Latexman]

10 m head (@ s.g. 0.8 for mineral oil) = 11.4 psi. Or was it 15 m head (1st post)? Anyway, not much head! Therefore, not much flow, since it's 3/4" pipe. I'd guess 5 U.S. gpm. I'll also guess this is for a very small reactor. Maybe 10-50 U.S. gallons? Is it lab or pilot plant scale?

Good luck,
Latexman

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[Latexman]

"We have thermic fluid heater of 1,00,000 kcal/hr capacity."

Is that 100,000 or 1,000,000 kcal/hr? I'd guess 100,000.

Good luck,
Latexman

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[LittleInch]

There's something not right between the pump power and the pipe size and pump head. Flow would seem to max 5m3/hr based on pipe size, but much bigger if the pump size is used. Only about 10% of the info any one would need to give a proper answer.



My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Latexman]

Motor nameplates can be misleading. The power is there for the taking, if needed. If not needed, the nameplate remains the same, but the power draw doesn't. Of course, I've seen plenty of pressure gauges that read incorrectly too, and the stated head could just as easily be off. Not enough data. All one can do is guess.

Good luck,
Latexman

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[MilanMhatre]

@Latexman: 10 to 15 m head .... And BATCH size 2-3 ton (500-600 gallon) ....

 

[Latexman]

Attach the P&ID please.

Good luck,
Latexman

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[MilanMhatre]

Pl find attached oil circulation diagram.

When both valves are closed oil is use for heating( upto 230C) purpose and when valves are open oil is used for cooling( upto 80C) purpose.

Problem is, we have to reduce temp 230C to 80C of reactor in cooling operation but it took 5hrs to drop down that much temp.

do u have any suggestion so we can reduce time by 2hrs??

 

[Latexman]

I was also hoping to see all the existing instrumentation in one shot, because I'm starting to tire of trying to drag information out of you.

Good luck,
Latexman

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[LittleInch]

Milan,

If you want actual numbers, then give us all the details such as,

Mass of oil, heat capacity of oil, heat capacity of your reactor, cooling water flow rate, HX size, type and efficiency.

Otherwise you need to either double the size of your HX or probably triple the cooling water flow through it.

Before you start the reaction, how long does it take your reactor to heat up? That will give you some idea of the heat flux in the reactor which needs to be chilled down.

Can the reactor cope with a faster cool down?

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[MilanMhatre]

@All of Above :

In our plant designed not by engineer so it's very difficult to know all parameters.
That's why i lagging to calculate Heat capacity and all balances.

I m providing here all details.

Batch Reactor( Jacket Type) capacity 2 tons : product- Glycerine monostearate (GMS)

Raw products: Stearic acid + glycerin

Reaction started at 60C and over at 240C

Thermic Fluid Heater capacity: 100,000 kcal/hr, mounted with 3 HP pump for oil circulation( pipe dia 0.75' to 1").

Heat Exchanger( for cooling down product temp from 240C to 80C), took 5-6 hrs for cooling.

FRP Cooling Tower: Out temp 26C and In temp 31C( not sure but considering diff of 5C)
Centrifuge pump of 2" to 2.5" suction and about 10M head for water cirulation.


Give me suggetion which ll help me to reduce the cool down product temp as early as we can.

 

[MilanMhatre]

And one more thing we also have Chloro Sulphuric Acid reaction which is incompatible with Water, metals, acids, bases, alcohols, amines,
metals and plastics.
Which type of pump is suitable for it ?? Teflon is workable ??

We transport it by vacuum, is any other way to discharge it??

 

[LittleInch]

Still don't have anywhere near enough the data that we need but at 116kW input you have a lot of heat going in which clearly heats up a substantial mass in the reactor. Your cooling water supply looks ok at that sort of temp difference if indeed that is the in and out of your HX, so my thoughts are heading towards the lack of oil flow to transport the heat from the reactor to the HX.

For cooling you probably need to increase the diam of the oil pipe outside the reactor and double or triple the oil flow rate.

What is the typical temp difference of the oil in and out of the HX?

Don't introduce brand new subjects halfway through a post. Start a new post for your acid question.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Latexman]

Please list every temperature and flow measurement on the reactor, oil, and cooling water systems.

Good luck,
Latexman

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[MilanMhatre]

As i already said , lack of flow measurement and temp measurement device....

Heat exchanger oil in at 220C and out at 205C tentative.

but when temp goes down this temp difference become smaller and at 120C ( HX in temp) the output temp is 108 or 107C.

 

[LittleInch]

Milan,

Your HX is simply too small - how big is it / what type ?

Add another similar sized / identical one in series with the oil flow and you will cool down a lot faster ( not twice as fast, but close to it).

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way