2 replies to this topic

[Guy Masin]

Hello all,
I have a question, may one of you more experienced chemical engineers can help me,
I want to calculate the amount of steam needed to clean a designated vessel.
The steam characteristics are: 3.5 barg, 200°C, the vessel's volume is 25m3.
The steam has to clean a viscous wax - kinematic viscosity @80°C 8.3mm2/s, desity@70°C= 797 kg/m2 and boiling range of 430-620°C.
Thank you

[ankur2061]

Hello all,
I have a question, may one of you more experienced chemical engineers can help me,
I want to calculate the amount of steam needed to clean a designated vessel.
The steam characteristics are: 3.5 barg, 200°C, the vessel's volume is 25m3.
The steam has to clean a viscous wax - kinematic viscosity @80°C 8.3mm2/s, desity@70°C= 797 kg/m2 and boiling range of 430-620°C.
Thank you

Guy Masin,

Before we get down to your question of steam quantity calculation, you need to tell us what limitation you have on steam availibility? Because if you ask some of us experienced engineers, then we would not even bother to calculate the steam quantity, since it is simply not worth the exercise. We would just continue to do a steam-out operation till the viscous wax has all melted & run down from the low point vessel nozzle. The one thing we would ensure before starting the steam-out operation is to check whether the vessel design conditions (pressure/temperature) can permit a steam-out such as whether the vessel is designed for vacuum which can occur due to condensation of steam during the steam-out operation.

In fact I would ensure that I have enough steam available till the cleaning operation is completed which most certainly would not be a steady state operation since there will be interrruptions to check the cleaning performance & introduce other methods to flush out the waste wax.

Hope this helps.

Regards,
Ankur

[Qalander (Chem)]

Congrats;

you have got a very pertinent reply from our friend ankur.

I suggest few points to consider,which may impact steaming-out objective.

Vessel's Geometrical shape and placement(vertical or horizontal).

Vessel's insulation (externally) existing and its properties/capabilities to withstand possible temperatures reached.(in a way hinted by Mr.ankur as well)

In relation to the insulation mechanical integrity and/or possible fire hazard, as occasionally fires occur at process plants consequently in similar circumstance.

Hope this helps in some way!