HHV - LHV of landfill gas

[choi1167]

The difference between the High Heat Value (HHV) and the Low Heat Value (LHV) is the Latent Heat of Vaporization (Evaporation). For natural gas it's about 10%. How about for landfill gas?

 

[choi1167]

Any information on landfill gas properties, tables, etc.?

 

[choi1167]

Am I in a wrong forum?

 

[owg]

Landfill Gas (LFG) is about 50% methane. The rest of the gas varies but includes moisture, mercaptans, CO2, etc. Google finds lots on the subject. Re HHV and LHV you may have to do the math.

Here is an excerpt from a Google hit.

LFG can be classified into three categories, based on the level of pretreatment/processing prior to utilization. These are:

Low-grade LFG fuel - Utilization of LFG as a low-grade fuel typically requires minimal processing, involving condensate removal chamber(s) as part of the LFG collection system and moisture knockout pots to reduce the amount of moisture in the gas stream.

Medium-grade fuel - Additional gas treatment devices are used to extract more moisture (with contaminants) and finer particulate matter. The process typically involves compression and refrigeration of LFG and/or chemical treatment or scrubbing to remove additional moisture and trace gas compounds such as mercaptans, sulfur compounds, siloxanes, and volatile organic compounds.

High-grade fuel - Utilization of LFG as a high-grade fuel involves extensive gas pretreatment to separate the carbon dioxide and other major constituent gases from the methane and to remove impurities including mercaptans, sulfur compounds, hydrogen sulfide and volatile organic compounds, and gas compression to dehydrate the gas.

Low- and medium-grade fuel produced from LFG has a heating value of approximately 16.8 MJ/m3. This heat value is roughly one-half the heating value of natural gas. LFG that has been further processed and treated to produce high-grade fuel has a higher heating value (37.3 MJ/m3) than low and medium grade fuel, and can be substituted directly for natural gas in pipeline applications (CRA, 1996).




HAZOP at

http://www.curryhydrocarbons.ca

 

[Montemayor]

choi1167:

To say that the LHV is 90% of the HHV for natural gas is to generalize. Do you mean at the wellhead? - or at the burner tip?

Without specifics you can't get a specific answer. In order to find the HHV (or LHV) of any gas, you require the composition. As OWG well points out, Landfill Gas can be about 50% - but what is the rest? You could wind up with a non-burnable gas - or one that requires special burners and other details that it wouldn't be practical as a fuel. Can you furnish an analysis?