calculating MSW to SAF LCA

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6 months 3 weeks ago #506 by ahsansyed442
calculating MSW to SAF LCA was created by ahsansyed442
I'm trying to model an MSW to a renewable jet pathway using FT. I see that there are RDF to various fuels and MSW to RDF, but I couldn't find any way to convert MSW to jet fuel (similar to the pathway in GREET). I also had questions about the way that landfill diversion credits are assigned - these are only included in the RDF pathway but not in any MSW pathways. 

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6 months 3 weeks ago #507 by doconnor
Replied by doconnor on topic calculating MSW to SAF LCA
To model a Msw to FT pathway directly there are a couple of steps to take.

1. Set the FT fuel properties on the Fuel Char sheet to match those of the SAF that you are producing. The energy and volumetric densities and the carbon content of the fuel are the important ones.

2. Set the RDF fuel properties on Fuel Char to be the same as the RDF and make sure that it is representative of your feedstock. The energy density is critical.

3. If the fuel processing information is included in the mass and energy information is included in the fuel production information then you can zero out the RDF stage. In column CA on the input sheet zero the electricity and all but 0.001 MJ of NG

4. Adjust the mass input in column CA so that the upstream emission for the SW to RDF pathway is zero except for the avoided emission.

5. With these changes the RDF to FTD pathway will become a MSW to SAF pathway.

6. The avoided emissions have three parameters that can be set. The first is the methane emissions from MSW from a landfill. This is cell F48, the default value is 90 g CH4/dry kg of MSW. The second is the renewable C content of the MSW, cell F44 (default is 0.70) and finally the fraction of methane avoidance that will be accepted in a regulatory system (F45).

The avoided methane emissions in column CA gets carried through to the FTD pathway and shows up as avoided emissions there.

I hope that this helps.

Don O'Connor

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6 months 1 week ago #510 by ahsansyed442
Replied by ahsansyed442 on topic calculating MSW to SAF LCA
Thanks for this. If the facility or project utilizes additional hydrogen (that does not come from the MSW), is there a way to account for that in the model?

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6 months 1 week ago #511 by doconnor
Replied by doconnor on topic calculating MSW to SAF LCA
The hydrogen consumption is entered on the Alt Fuel Production sheet. The pathway is in column E and hydrogen is n row 44.

The units are kg/litre.

Regards
Don O'Connor

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6 months 3 days ago #512 by ahsansyed442
Replied by ahsansyed442 on topic calculating MSW to SAF LCA
Hello again - I have the energy density (MJ/kg of MSW) - how should I reflect this? Should I change the energy density in the fuel char tab of the RDF or the MSW? What impact does the input tab CA247 have on the calculations? I'm finding I can't zero this out and I can't increase it to reflect the energy density of the MSW I'm working with...

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6 months 1 day ago #513 by doconnor
Replied by doconnor on topic calculating MSW to SAF LCA
Your should use the energy density for the RDF value on the Fuel Char sheet.

To turn the RDF to FT pathway to a MSW to FT pathway, set CA 243 to zero and CAS 245 to 0.1.

Then adjust CA 247 until DY11 on the upstream emissions sheet is 0. A value of 95.4 will do it for the default, but the value will be different after you adjust the energy content of your RDF.

Don O'Connor

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