How do I measure BTU content of my gas supply 1

[pesy]

I am looking for an instrument that measures the BTU content of natural gas. My utility company says they give us anywhere from 1000 to 1030 BTU/ft3, but I've also heard that they really provide less.

 

I doubt there is an instrument out there that will provide a measure. You can calculate your fuel's BTU content using pounds of steam produced, pressure you are producing steam at, and boiler efficiency. For example:

Steam being produced at 100 PSIA at a rate of 1000 lbs/hr, in one hour

1000 lbs of steam has been produced generating 1187.2(1000) = 1187200 BTU's
(the 1187.2 came from the steam tables)

If your boiler is 80% efficient, N(0.8) = 1187200 = 1484000 BTU's were transferred from the fuel to the feedwater. For natural gas, if 1250 cu.ft. of gas was burned, then: 1484000/1250 = 1187.2 BTU's per cubic ft. of gas. (the 1250 was an arbitrary number, you need to get that number from your meter.) [sig][/sig]

 

[pesy]

I'm looking for a gas calorimeter. It burns a sample of known CH4 and compares the energy released to a burned line sample of CH4. They are out there- but they are very expensive. The cheapest I found was $12,000- but all the ones I've seen give me much more info than I need- I just need BTU content, not Wobbe index, etc. So I'm hoping there's a company out there that makes a basic one for significantly less $$. [sig][/sig]

 

If you are wondering about BTU content for your home, you are out of luck. Gas chromatography equipment is expensive. If you are wondering about measuring gas for a business using large amounts of natural gas a $20,000 cost could be easily justified by the rising cost of natural gas. I believe the latest figure is about $6/dekatherm.