8 replies to this topic

[miz19]

Hello there, 

 

Our engineering team is designing a flare and venting system for a upstream oil and gas plant. We are interested to know if cold gases or CO2 from vent is enough (incase of any emergency) to extinguish the flame of flare? We are intended to use commercial flare simulation software, but not much information is available for that. So any professional help on resources or guidance would be appreciated. 

 

Thanks in advance 

[fallah]

Hello there, 

 

Our engineering team is designing a flare and venting system for a upstream oil and gas plant. We are interested to know if cold gases or CO2 from vent is enough (incase of any emergency) to extinguish the flame of flare? We are intended to use commercial flare simulation software, but not much information is available for that. So any professional help on resources or guidance would be appreciated. 

 

Thanks in advance 

 

Hi,

 

Are you going to extinguish the flame of flare?

[miz19]

 

Hello there, 

 

Our engineering team is designing a flare and venting system for a upstream oil and gas plant. We are interested to know if cold gases or CO2 from vent is enough (incase of any emergency) to extinguish the flame of flare? We are intended to use commercial flare simulation software, but not much information is available for that. So any professional help on resources or guidance would be appreciated. 

 

Thanks in advance 

 

Hi,

 

Are you going to extinguish the flame of flare?

 

We are interested to find out, if CO2 content is enough to extinguish flame or not. 

[breizh]

Hi,

You may need to make a simulation (dispersion model) to assess the risks.

You should consider hiring a contractor familiar with this topic to support and provide a report. 

Definitely a discussion with insurance broker responsible for your facility is needed, same with fire brigade.

This is the responsibility of your manager to decide what to do and allocate the resources for the task.

Safety first.

Good Luck

Breizh

[shvet1]

Some practices do exist but applying those bear in mind that there are some ranges in C:H:O:S, imperfection of mixing, exit velocity and many other factor behind those.

Hope your supplier is experienced enough as those can be assured only by flaring a test gas on a test flare and a little companies in this world have provided those. I have visited one of those test fields and I should warn you such toys are extremely expensive.

 

EPA/452/B-02-001

1.1.3.2 Flare Specifications

...

Requirements for steam-assisted, elevated flares state that the flare shall be designed for and operated with:

...

• the net heating value of the gas being combusted being 300 Btu/scf or greater.

 

Fluor's Flare System Process Design Manual

9.2 TYPES OF FLARES

9.2.1 Discussion

...

Assist fuel gas is usually required to ensure complete combustion of gases having a lower heating value below 150 Btu/SCF (5,610 kJ/Nm3, 1,340 kcal/Nm3 ). Ammonia has a lower heating value of 365 Btu/SCF (13,600kJ/Nm3, 3,248 kcal/Nm3 ) and may require assist fuel gas to ensure complete combustion while minimizing nitrogen oxide production. Gas streams containing sulfur compounds (for example, sulfur plant tail gas) require a minimum lower heating value of 250 Btu/SCF (9,316 kJ/Nm3, 2,225  kcal/Nm3 ) for complete combustion.

The second criterion is gas analysis. The CO2 content of the gas radically affects the heat content required to sustain combustion.

The gas assist requirement also depends on the flare tip design and the flare gas exit velocity. In any case, a flare vendor should be consulted about the fuel gas requirement when a low heat content gas is to be flared.

 

ExxonMobil's std. 15E

FLARING OF H2S STREAMS

...

Incomplete or no combustion of flared hydrogen sulfide can lead to extremely dangerous situations because of the relatively low lethal concentration of hydrogen sulfide. Concentrated streams of hydrogen sulfide can be flared safely provided the following features are incorporated into the flare design (these features equally apply to those  locations where a dedicated H2S flare is not available and concentrated H2S streams are handled via the regular hydrocarbon flare):

...

The combustion characteristics of the flared gas must be high enough to ensure flame stability. Typical refinery H2S streams containing H2S, CO2 and water vapor are  flammable without assist gas if the UFL is 30 vol. % or higher. If UFL is below 30 vol. %, it is recommended that assist fuel gas be added until the UFL is increased to 30 vol. % or the heating value increased to 500 Btu/SCF (5.2 kJ/Sm3). Hydrogen rich streams will increase the UFL and paraffin hydrocarbon streams will increase the heating value. Supplemental fuel gas, when required, should be automatically introduced (at the upstream end of the flare header for mixing and purging) via ratio control of the fuel gas  stream to the measured flare header acid gas rate. Ratio control of fuel gas/acid gas should be a safety critical instrument.

...

 

Edited by shvet1, 17 July 2024 - 12:57 AM.

[carlos infante]

I don understand why do you wants to extinguish the flame?

 

Flare are design to handle and burn HC gases to avoid inflamable gases plume around the facilities.

 

Carlos

[shvet1]

He doesn't want to extinguish the flare, he wants to burn a CO2-rich vent.

[miz19]

Thanks for your response. Yes we don't want to extinguish the flame. The flare and vent are in close proximity, and the vent composition comprises of 70-80% CO2, so we are curious about the worst case, if the CO2 will be enough to engulf the flare tip and affect the flammability. Also if I am interested can we carryout some 3D analysis as well. For instance. https://www.linkedin...-james-pickles/

 

 

 

He doesn't want to extinguish the flare, he wants to burn a CO2-rich vent.

[shvet1]

Yes, you can, e.g.

3D flame-shape analysis

Flaresim provides full 3D flame-shape analysis with complete flexibility in the location and orientation of multiple stacks, and rapid evaluation of flare systems under different wind speeds and directions. Shield options can be included.

Link https://www.slb.com/...tware/flaresim 

Edited by shvet1, 31 July 2024 - 08:40 AM.