Creating a Flammable Mixture
Creating a Flammable Mixture
(OP)
Hi
A post from the UK.
I've been asked to calculate the amount of Fuel Gas that would nee to be added to an acid gas stream to create a flammable mixture. I have a full Hysys simulation to hand so physical properties are readily available.
Any suggestions??
A post from the UK.
I've been asked to calculate the amount of Fuel Gas that would nee to be added to an acid gas stream to create a flammable mixture. I have a full Hysys simulation to hand so physical properties are readily available.
Any suggestions??





RE: Creating a Flammable Mixture
Dangerous association...
RE: Creating a Flammable Mixture
I'm interested in making a very rough estimate of the amount of fuel gas need to be blended into the stream without having to go to flare tip vendors.
RE: Creating a Flammable Mixture
1/LFL_mix = y_1/LFL_1 + y_2/LFL_2 ...
y's are mole fraction, LFL the lower flammability limit. Same equation applies for UFL.
As an aside, is flaring the acid gas BAT? I don't know the answer, but am curious.
Matt
RE: Creating a Flammable Mixture
If you assume the acid gas has 0 BTU's and natural gas has 1000 BTU's, then 1/3 natural gas, 2/3 acid gas.
RE: Creating a Flammable Mixture
Without knowing what the composition is of the acid gas or which fuel gas you are using, I can't tell you what concentration to enrich the acid gas too. However normally depending on how you plan to control the fuel gas rate, you would take the concentration to at least 25-50% above the UFL of the mixture before you get anywhere near the flare tip.
I hope that helps.
RE: Creating a Flammable Mixture
RE: Creating a Flammable Mixture
The 300 BTU/cu.ft that you mention seems to agree well with the practical experience of landfill gas flaring and power generation.
In many US landfills, when the gas vented from the landfill is flared or sent to an internal combustion engine, the BTU content must be about 300 BTU/Cu.ft or higher.
Typical landfill gas consituents are methane, CO2, N2, O2 and traces of others
-MJC