6 replies to this topic

[franchescamarie]

What should I consider in sizing tank heating coils?

I have a 4 MB tank which shall be heated to 180 deg C by using an MPS (221 deg C, 150 psig)

[ankur2061]

franchescamarie,

 

If you provide certain data I can size the heating coil if it is a batch heating process using an agitator and a steam coil.

 

Data Required:

 

1. Vessel Diameter

2. Agitator Diameter

3. Agitator Speed (rpm)

4. Type of Agitator (Turbine / Paddle / Propeller)

5. Mass of batch

6. Initial Batch Temperature

7. Final Batch Temperature

8. Batch heat-up time, hours

9. Density of Process Fluid @avg temp (Initial Temp + Final Batch Temp / 2)

10. Thermal Conductivity of Process Fluid @avg temp (Initial Temp + Final Batch Temp / 2)

11. Viscosity of Process Fluid @avg temp (Initial Temp + Final Batch Temp / 2)

12. Specific Heat of Process Fluid @avg temp (Initial Temp + Final Batch Temp / 2)

13. Outside Fouling factor

14. Steam Pressure (if saturated) or  steam pressure and temperature (if superheated) (It is advantageous to use saturated steam for heating coils)

15. Inside Fouling factor

 

The results will include coil helix diameter, coil surface area and coil length.

 

Regards,

Ankur.

[PingPong]

@francescamarie

 

I have a 4 MB tank which shall be heated to 180 deg C by using an MPS (221 deg C, 150 psig)

Note that the MPS superheat temperature of 221 ^oC is irrelevant, it is the condensing temperature that matters.

 

That MPS steam will have a condensing temperature of only 185 ^oC at 150 psig, which is hardly adequate to keep your tank at 180 ^oC.

Edited by PingPong, 09 October 2015 - 01:00 PM.

[SPC]

Hi,

 

 Your requirement is indirect bath heating, if this is the case, kindly furnish details for :

 

1) Bath fluid 

 

2) Heating medium for Bath fluid is MP Steam.

 

Regards,

SPC

[barbara_s]

Ankur

 

I have an agitated and heated tank with palm oil.

I have a question for you:

 

The h for steam in a coil in 8000 W/m^2 °C, but if I want to calculate the value, which equation I have to use?

 thks for you help

[ankur2061]

Hi Barbara,

 

The service heat transfer coefficient for condensing steam is empirically derived. I don't have any equations for deriving the value. While trying to answer your query I checked my library and one of the standards I have, mentions it as 1000 Btu / hr-ft^2-F (5675 W/m^2-C) for condensing steam to coil wall which is lower than what you have mentioned, The heat transfer book "Process Heat Transfer" by D. Q. Kern mentions 1500 Btu / hr-ft^2-F (8500 W/m^2-C) for condensing steam in coil.

 

Regards,

Ankur.

[barbara_s]

Ankur

 

thks for your reply!