4 replies to this topic

[Narayanan.u]

Hi All,



We need to select the capacity of liquid Co2 required for providing protection to the burner chamber of a diesel fired heat exchanger. Medium TEG used to heat associated gas feeding a power plant.

It is based on the chamber volume as per my information. The Co2 concentration need to be raised to 30% or higher.


Could anyone give some tips on the calculations to arrive at how many Kg liquid Co2 needed based on the volume of the chamber.


Thanks in advance.


U.Naryanan

[Art Montemayor]

U. Naryanan:

I don't know where your direct-fired heater is located or what country or jurisdiction you are in, but I was involved in producing many, many tons of CO2 for portable fire extinguishers in my early years and I still retain a little knowledge of this industry. You should immediately contact your local Fire Marshall or public official in charge of fire safety in your locality. You should confirm that the application of a liquid CO2 fire extinguisher is approved for your application. It is the local authorities who determine and regulate the quantity, quality, and capacity of fire extinguishers employed in their jurisdiction – not the user. At least, that is the way this situation is handled in practically all countries I have worked in or visited. To my knowledge there is no "magic formula" or "equation" that will conveniently calculate out the answer to your dilemma. Additionally, bear in mind:

• Liquid CO2 extinguishers operate by producing a 2-phase mixture of gaseous and solid CO2, both at a temperature of -109 oF (-78 oC). Your firing chamber is going to receive a violent thermal shock and will probably be subjected to severe thermal stresses.
• The rapid sublimation of the solid CO2 will cause a very rapid generation of additional gas in the chamber and will probably require careful and detailed calculations for making sure that the chamber is not over-pressurized by the introduction of excess amounts of CO2.

Introducing CO2 alone will not eliminate a very dangerous situation from evolving. You must also ensure that ALL fuel to the chamber is positively and automatically safely blocked off. This means a complete and approved emergency instrumentation circuitry that must undergo Management of Change and the usual Hazops. All of this will be the business of local authorities, I presume.

[Narayanan.u]

Dear Art,

Thanks for the reply and advise. I am in Yemen. We don't get that much professional suppliers here.

Definitely the CO2 is not going to be introduced into the chamber. It is only for outside protection to put off in case small fire occurs around.

Regards,

Narayanan

[kevinlewis]

U. Naryanan:

I don't know where your direct-fired heater is located or what country or jurisdiction you are in, but I was involved in producing many, many tons of CO2 for portable fire extinguishers in my early years and I still retain a little knowledge of this industry. You should immediately contact your local Fire Marshall or public official in charge of fire safety in your locality. You should confirm that the application of a liquid CO2 fire extinguisher is approved for your application. It is the local authorities who determine and regulate the quantity, quality, and capacity of fire extinguishers employed in their jurisdiction – not the user. At least, that is the way this situation is handled in practically all countries I have worked in or visited. To my knowledge there is no "magic formula" or "equation" that will conveniently calculate out the answer to your dilemma. Additionally, bear in mind:

• Liquid CO2 extinguishers operate by producing a 2-phase mixture of gaseous and solid CO2, both at a temperature of -109 oF (-78 oC). Your firing chamber is going to receive a violent thermal shock and will probably be subjected to severe thermal stresses.
• The rapid sublimation of the solid CO2 will cause a very rapid generation of additional gas in the chamber and will probably require careful and detailed calculations for making sure that the chamber is not over-pressurized by the introduction of excess amounts of CO2.

Introducing CO2 alone will not eliminate a very dangerous situation from evolving. You must also ensure that ALL fuel to the chamber is positively and automatically safely blocked off. This means a complete and approved emergency instrumentation circuitry that must undergo Management of Change and the usual Hazops. All of this will be the business of local authorities, I presume.

I agree with the above mentioned post. The CO2 is an easily available element that can be use for extinguishing fire. It is good to use CO2 as fire extinguisher for making the process risk free and less harmful.

[Qalander (Chem)]

U. Naryanan:

I don't know where your direct-fired heater is located or what country or jurisdiction you are in, but I was involved in producing many, many tons of CO2 for portable fire extinguishers in my early years and I still retain a little knowledge of this industry. You should immediately contact your local Fire Marshall or public official in charge of fire safety in your locality. You should confirm that the application of a liquid CO2 fire extinguisher is approved for your application. It is the local authorities who determine and regulate the quantity, quality, and capacity of fire extinguishers employed in their jurisdiction – not the user. At least, that is the way this situation is handled in practically all countries I have worked in or visited. To my knowledge there is no "magic formula" or "equation" that will conveniently calculate out the answer to your dilemma. Additionally, bear in mind:

• Liquid CO2 extinguishers operate by producing a 2-phase mixture of gaseous and solid CO2, both at a temperature of -109 oF (-78 oC). Your firing chamber is going to receive a violent thermal shock and will probably be subjected to severe thermal stresses.
• The rapid sublimation of the solid CO2 will cause a very rapid generation of additional gas in the chamber and will probably require careful and detailed calculations for making sure that the chamber is not over-pressurized by the introduction of excess amounts of CO2.

Introducing CO2 alone will not eliminate a very dangerous situation from evolving. You must also ensure that ALL fuel to the chamber is positively and automatically safely blocked off. This means a complete and approved emergency instrumentation circuitry that must undergo Management of Change and the usual Hazops. All of this will be the business of local authorities, I presume.

I agree with the above mentioned post. The CO2 is an easily available element that can be use for extinguishing fire. It is good to use CO2 as fire extinguisher for making the process risk free and less harmful.

Dear Narayanan.u
Art's reply is quiet accurate and fire safety plan should include positive fuel source cut-off and quantum minimization strategy in place.
one small reminder about any humans around and getting any sort of exposure;needs to be taken care since Co2 pushes away oxygen and asphyxiation danger is present, also if the chamber may contain volatile flammable gas(vapour) air ignitable mixtures then the Co2 dispensing system should be properly bonded/grounded to take care of static charge generated during fast speed Co2 emission.
hope this helps
Regards
Qalander