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#1




Natural Gas CFM Into BTU/M Gas Composition Given
HI Guys;
I am hamad from pakistan and working in gas turbine compressor sets. i want to know how we convert the flow in btu. we measure the flow in cubic feet/h and want to convert into btu/hour. the gas composition is as under gross dry btu=914.47 gross sat btu=898.56 nitrogen=9.4550 co2=1.8590 ch4=87.1810 please help me on this issu Thanks 
#2




Re: Natural Gas CFM Into BTU/M Gas Composition Given
Quote:
Welcome. The two BTU figures given are per cubic foot. I am not entirely sure what is meant by dry and saturated btu. I am guessing dry means as analyzed after water vapor is removed, but that changes the volume. If saturated means water vapor is present at the saturated vapor pressure (for the temperature), that may understate the btu content. If you need a highly precise result, you need to know the actual water vapor content as supplied (and saturated vapor pressure) and interpolate between these two figures. For a rough estimate, you could use a midpoint, assuming the gas is neither bonedry nor saturated. 
#3




Re: Natural Gas CFM Into BTU/M Gas Composition Given
Thanks For Reply
i think dry gross btu=HHV or CV then how i use this to convert CFM to BTU/M 
#4




Re: Natural Gas CFM Into BTU/M Gas Composition Given
Quote:
Simply multiply by the flow in cubic feet per hour to get BTU/h Unlike the metric system, the Imperial system (and US Customary) often use the Roman numeral M for thousand and MM for million. Is that what you meant by the M in your question? 
#5




Re: Natural Gas CFM Into BTU/M Gas Composition Given
Hi
Thx for reply First we use M for thousands and MM for million. Secondly the gas turbine engine test report from the manufacture shows the fuel flow value at full load is 37.01 mmBTU/HR while the gas composition is as under Methane=94.4199 Eathane=1.0500 Propane=0.2800 IButane=0.0600 NButane=0.0600 IPentane=0.0300 NPentane=0.0200 Carbon dioxide=0.0200 Nitrigen=3.8900 Oxygen=0.1700 while they use LHV(BTU/SCF)=887.5 S.G=0.5816 and woob index at 60 farenhite is 1163.8 when we measure at site at the same load and speed the value is diffrent. if we get 47.3 scf/HR then what will be BTU/HR in our case? Can we calculate The LHV and HHV if gas composition knows if possible then how? thanks for hep 
#6




Re: Natural Gas CFM Into BTU/M Gas Composition Given
Quote:
LHV and HHV for a mixture like natural gas is calulated by taking the percentage of each gas,the HHV and LHV values for that gas and constructing a weighted average. In your data, you would only need to consider the methane through pentane, the remainder don't contribute. The US Dept. of Energy has a fuels table which gives average data by fuel type. They give 1089 BTU/ft³ HHV and 983 BTU/ft³ LHV (these values are at 32 °F, or "normal" conditions in the metric system rather than "standard". Figure 94.6% of these values at 60 °F for "standard"). I don't have a reference for HHV and LHV of all the individual gases. I found a calculator on the web once, but lost the link. 
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