Bill Freeman wrote:

Paul,
Biogas is mostly methane, highly variable, but often a bit
poorer than natural gas (~1000 BTU/ft3 is typical, altho
this is driven by contracts, some is 900).   Should burn
much like LP gas with a proper carb.  Probably a bit less
power per cubic inch.

Bill

What are some of the other constituents of natural gas and bio gas?
Oxygen? Sulfur dioxide? Nitrogen? Carbon dioxide? Etc., etc..
As I understand it this Ingersoll Rand NG burning huge rotary engine had
problems with the quality of the NG.

Perhaps a computer can analyze the gas quality real time and
adjust the mixture on the fly. Perhaps the gas can economically
be pre processed to remove undesirable constituents.

If crude oil were $50 a barrel almost anything would be possible :-)

Paul Lamar

I believe they dilute NG with air in the pipeline to bring it down to
the contract BTU content, typically 900-1000 BTU.   Pure methane
is higher.  There are apparently some other fractions in it as it
originally is put into the pipeline, but a friend that buys fuels (including
NG) for a local electrical utility says the pipeline companys chill
the gas dropping out butane and propane, etc. and then dilute the
methane down to contractural levels and pass it on.  Sounds a
bit like stealing to me, since they then sell the liquified fractions
that they have pulled out.

I don't think there is much "pollution" in NG, since our gas turbines
ran VERY, VERY clean years ago at Union Carbide.  When we ran
them on "distillate" - similar to kerosene, they crudded up a lot
faster, which is why we and (esp) CA turbine topping power units
really like NG for fuel.  And since you can't put a coal fired powerplant
in CA, CA is pulling so much NG out of the rest of the country
that my NG prices have tripled this year.

Bill

 
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