+1 vote

Hello to all,

I observed in the specific process "ethanol production from sugarcane | ethanol, without water, in 95% solution state, from fermentation | Cutoff, U" that, when building the product system without cutoff, the downstream process "dewatering of ethanol from biomass from 95 to 99.7% solution state....." is automatically added. Why does the software do this? 

in openLCA by (280 points)

1 Answer

+1 vote
by (10.9k points)

It looks like a downstream process in the model graph initially ...

... but it is a loop: like for electricity, to produce ethanol there is some amount of ethanol used in the supply chain. When you expand the nodes in the model graph and follow the input-output paths you should come back to the ethanol production process:

ethanol production

 -> dewatering of ethanol

  ->  market for ethanol

   -> ethyl tert-butyl ether production

    -> market for ethyl tert-butyl ether production

     -> phenylenediamine production

      -> market for meta-phenylene diamine

       -> seawater reverse osmosis module production

        -> tap water production

          -> market for tap water 

           -> ... and tap water is then used in many processes

            -> ...

             -> ethanol production