Making and Inert Gas from Hydrogen or Natural Gas
Making and Inert Gas from Hydrogen or Natural Gas
(OP)
Is it possible to mix hydrogen or natural gas with another gas to make them inert? If so what would this gas be? Please be specific.
Thanks in advance, Nigel.
Nigel Waterhouse
n_a_waterhouse@hotmail.com
A licensed aircraft mechanic and graduate engineer. Attended university in England and graduated in 1996. Currenty,living in British Columbia,Canada, working as a design engineer responsible for aircraft mods and STC's.
Thanks in advance, Nigel.
Nigel Waterhouse
n_a_waterhouse@hotmail.com
A licensed aircraft mechanic and graduate engineer. Attended university in England and graduated in 1996. Currenty,living in British Columbia,Canada, working as a design engineer responsible for aircraft mods and STC's.





RE: Making and Inert Gas from Hydrogen or Natural Gas
Best Regards
Morten
RE: Making and Inert Gas from Hydrogen or Natural Gas
Inert gas generation units are now common in the oilfield for underbalanced drilling. Try http://www.northlandenergy.com/control_press_drill_gassupply.htm for a basic explanation, basically they burn a fuel gas, scrub it, and pump it down an oil well to lighten the hydrostatic head of the column of drilling fluid. Could also be used for purging, inerting. Tankers have been using a similar system for years to inert the cargo holds.
RE: Making and Inert Gas from Hydrogen or Natural Gas
If I had a tank of CNG, LPG, or hydrogen, what proportion of intert gas would I need to add in order to prevent combustion? In the event of a leak would they stay mixed long enough to prevent combustion? I am not a chemical engineer, so please forgive my apparent ignorance in this area.
If anyone knows where I could get more info on this matter please let me know.
Nigel Waterhouse
n_a_waterhouse@hotmail.com
A licensed aircraft mechanic and graduate engineer. Attended university in England and graduated in 1996. Currenty,living in British Columbia,Canada, working as a design engineer responsible for aircraft mods and STC's.
RE: Making and Inert Gas from Hydrogen or Natural Gas
All gasses that can ignite has something called a Lower Explosive Limit (shorted _LEL_ the b..... editor turned it into a laughing face) and also a Upper Explosive Limit. You can find this in many physical databook (i dont have any here). If you have a mixture use weighted mol. average.
If you have a gas with no oxygene this gas could not ignite if you added a spark. If you start to add atmosperic air then at a certain dillution a sparc would cause an explosion. Continue to adding air and at another lower dillution the spark would no longer cause an explosion.
So if you dillute with N2 until below lower explosive limit then your gas mixture cannot ignite. But this is prob. below 20% of your HC/H mixture.
I dont know of any "magic component" that could be added in trace amounths to prevent ignition.
Best Regards
Morten
RE: Making and Inert Gas from Hydrogen or Natural Gas
Think of any combustion engine, think of the fuel mixture
Lower Explosive limit (LEL) = Lean mixture, not enough fuel/too much air
Upper Explosive Limit (UEL) = Rich mixture, too much fuel/ not enough air
RE: Making and Inert Gas from Hydrogen or Natural Gas
Use a reliable vendor for the nitrogen, Union Carbide, Praxair, Liquid Air, Air Products, etc. Some of these may have merged or changed names. Inert gas generators can make corrosive gas, not recommended.
Visit www.curryhydrocarbons.ca for more.
RE: Making and Inert Gas from Hydrogen or Natural Gas
RE: Making and Inert Gas from Hydrogen or Natural Gas
The posted limits of flammability (lean limit) for gases actually represents the amount of quench inert (nitrogen) in the air at the measured condition. When you replace nitrogen with carbon dioxide (for example) you need to rebalance the numbers to keep the heat absorbtive power of the CO2 the same as it was for the Nitrogen. Sounds long winded when I explain it this way!! It's actually a matter of not exceeding a miminum theoretical adiabatic flame temperature with whatever constituents you have.
Getting back to your actual problem, 1 vol of Hydrogen is, theoretically, just flammable in 16.5 vols of N2 or 10.3 vols of CO2.
1 vol of CH4 is just flammable in 4.2 vols of N2 or 3.3 vols of CO2. You could also use steam (roughly 4/3 as much as N2 by vol). Apply your own FOS to these numbers and don't be afraid to be over-conservative (ie. safe). The NFPA recommend using a value which relates to 25% of the LEL concentration. You could try the NFPA forum for more info.
I can send you a relevant page from BOM-503 and an interpretive LEL/UEL chart of my own, if you drop me an email at flareman_xs@netzero.net.
David