20 replies to this topic

[Kachisa]

Dear All,

Do you have any reference on max operating temperature of a propane vessel ?

For me, max ambiant temperature is 60 °C but the tank is equipped with a sun visor (sun shade).

 

If I need to consider the max operating temperature of a propane vessel is of 60 °C ?

And how about propane vessel design temperature in this case ?

 

A real industrial reference will be greatly appreciated.

 

Thanks.

Edited by Kachisa, 06 November 2017 - 04:03 PM.

[Bobby Strain]

We usually refer to vessel design conditions as X pressure at  Y temperature. Temperature alone is not sufficient. And for your case, the service is important, too. Ambient temperature is generally reference to a shaded condition.

 

Bobby

[Kachisa]

Mr. Bobby,

Thank you for your comment.

60 °C is max site temperature. 

I do not understand clearly your idea. Should I consider max operating temperature as max site temperature ?

Or it is  the shaded temperature ? If It is the case, how to estimate shaded temperature ?

 

Thank you in advance

Edited by Kachisa, 06 November 2017 - 05:43 PM.

[ankur2061]

Hi,

 

In your case the maximum operating temperature should be be considered the the maximum temperature recorded as "Dry Bulb Temperature" during the hottest month of the year and averaged out for previous years for the hottest months in those years.

 

Regards,

Ankur.

[Kachisa]

 

Thanks Mr. Ankur for your comment.

 

As this tank is equipped with a sunshade, I think it is not necessary to take into account Dry Bulb Temperature.

 

Please correct me if I al wrong.

 

Thanks 

[fallah]

Kachisa,

 

Due to applying a sun shade; yes you can consider max ambient temperature of 60 C as max operating temperature.

[Kachisa]

Kachisa,

 

Due to applying a sun shade; yes you can consider max ambient temperature of 60 C as max operating temperature.

 

Thank Mr. Fallah for your advice.

And how about design temperature ?

 

Thank you 

[fallah]

Kachisa,

 

The design temperature would be the max operating temperature plus a margin, say 5 to 10 C...
 

[Kachisa]

Thanks Mr. Fallah,

A last question : is it mandatory to take into account PSV discharge temperature as vessel design temperature ?

[fallah]

 

Kachisa,

 

I think you mean: "PSV relieving temperature", if so it should be considered as vessel design temperature if is the highest temperature to which the vessel might be subjected. The fire case is an exception for which in any case the relieving temperature wouldn't normally be considered in specifying the vessel design temperature.
 

[Kachisa]

Thank you so much Mr. Fallah.

I wanna mean PSV relieving temperature.

 

Why should not consider releiving temperature in fire case as vessel design temperature ?

Could you please refer me to a reference (API, ASME, etc.) which states what you did.

 

Thank you  a lot.

[fallah]

 

 

Because in most cases the fire relieving temperature is much more higher than other temperatures to which the vessel might be subjected.

 

The matter is mostly reflected in design practices and not in codes/standards...
 

[Kachisa]

I have an example : butane liquide is storaged in a propane reservoir that was designed @20 barG, 60°C.

In fire case, butane temperature could go up to 100 °C @20 barG.

 

If propane vessel PSV is adequate to answer to this kind of service. 

[fallah]

 

Considering provided info; vessel cannot tolerate such fire case conditions...

[Kachisa]

It means that the existing PSV of the existing propane vessel is not suitable when I use it to storage butane in fire case ?

[fallah]

 

The PSV has no problem but the relieving temperature of the fire case is higher than the vessel design temperature...

[Kachisa]

So, I can consider the existing propane vessel is not suitable to storage butane in fire case  without changing the existing PSV ?

Edited by Kachisa, 07 November 2017 - 07:13 AM.

[fallah]

When the vessel hasn't been designed for fire case it's not tolerate the fire case conditions, either containing propane or butane; but any vessel hadn't already been designed for fire case due to economical matters and because the fire case can be mitigated or managed by fire fighting facilities and measuring systems...
 

[Kachisa]

Thanks so much Mr. Fallah.

I got clearly what you explained and I totally agree with you.

However, in my case, this is a conversion project and the client willing not change anything.

A simple question : if the existing situation (propane vessel with PSV set at 20 barG @  60°C) is suitable to storage butane without modifying nothing ? It is evident that fire scenario exists when stocking butane. 

A simple answer Yes or No is waited. 

Edited by Kachisa, 07 November 2017 - 07:27 AM.

[ankur2061]

Dear Kachisa,

 

Have you checked the definition of "Dry Bulb Temperature". It says that it is the temperature of air measured by a thermometer freely exposed to the air but shielded from radiation and moisture. When it says shielded from radiation it means it is not exposed to the radiation from the sun, which implies that it is under a sunshade. Refer the link below:

 

https://en.wikipedia...ulb_temperature

 

Regards,

Ankur.

[Kachisa]

Thanks Mr. Ankur,

You are right !