10 replies to this topic

[panagiotis]

I would like to ask you if you could share with me any useful document, which elaborates the heat radiation calculation of jet fire Hydrogen?
Thank you in advance!

[breizh]

Hi,

Let you try your favorite search engine, key words: heat radiation calculation of jet fire Hydrogen

 

A lot of documents are available.

Breizh

[panagiotis]

Thank you Breizh! ☺️☺️☺️

[panagiotis]

Hi Breizh,
I used my favourite search engine. I found different curves. But, I couldn't find a relationship between the amount of hydrogen released and the heat radiated to the equipment. Or alternatively the amount of hydrogen released and the heat radiative fraction.

[breizh]

Hi,

Probably better if you can explain what you are trying to achieve! This will help us to support effectively.

Breizh 

[panagiotis]

Actually, I would like to find for jet fire of hydrogen a curve with the heat radiation and the amount of hydrogen in order to calculate the heat radiated to my equivalent.
I have found some graphs in different papers, which are about radiative heat fraction-residence time. But, I have not found a graph which correlated the amount of hydrogen with the heat radiated.
Is my question more clear now?

[Pilesar]

I think you probably need the net heating value of hydrogen to use in your calcs.

[breizh]

Hi,

I was expecting some info about the background of your project for better understanding.

Anyway, consider this resource to support your work:

https://h2tools.org/...drogen jet fire

 

A lot of data is also available in this link (properties, heating values,..),let you investigate .

 

It's not my area of expertise.

 

Breizh 

[panagiotis]

Actually, I have hydrogen jet fire and there is a vessel storage with hydrogen. And I need to calculate the temperature and pressure increase in the vessel because of this hydrogen flame.

[latexman]

Actually, I have hydrogen jet fire and there is a vessel storage with hydrogen. And I need to calculate the temperature and pressure increase in the vessel because of this hydrogen flame.

 

Have you read API 521, 7th Ed., June 2020, or earlier edition, on jet fires?  It has a lot of information.  There are 27 instances of the words "jet fire" in it.

 

Vessels are usually protected from a jet fire by other means than a relief device, so I question the need to calculate heat from a jet fire to a vessel.  A jet fire is hot, localised, and unpredictable; it can melt a hole in a vessel before much heat can go into the entire vessel contents.  Plant layout, insulation, fire walls, might be good choices.  API 521 says:

Instead of a pressure-relief system, protection against jet fires focuses on prevention of leaks through

proper maintenance and/or mitigation systems such as external insulation, depressuring systems,

isolation of leaks, equipment and/or flange orientation and minimization and emergency response.

Installation of external insulation provides additional time (an impinging jet fire can cause vessel

failure in less than 5 min, depending on the vessel’s wall thickness and material) but might not

prevent failure as the external insulation can be eroded by the momentum effects of the jet fire.

Depressuring systems are discussed in 4.6. Finally, unlike a pool fire, a jet fire can, in essence, be

“turned off” through isolation and depressurization of the jet fire source (i.e. leaking pipe, vessel, or

other equipment).

[panagiotis]

Thank you latexman! I am trying to make some sense out of the plethora of information. Little by little I am reading the API 521. There are many information on flare system, which is a good start understanding the topic.

Btw, your reply is helpful. I might come with more questions.

One thing that makes me confused is what is the difference between the radiated heat fraction and the radiant heat intensity (kW/M2) K? I am referring to the equation Hajek and Ludwig.