RE: Biomass Hydrogen Paper in 29 August Nature

From: Rich Blinne (richblinne@hotmail.com)
Date: Wed Sep 04 2002 - 12:27:25 EDT

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    ----Original Message Follows----
    From: "Glenn Morton" <glenn.morton@btinternet.com>
    To: "Rich Blinne" <richblinne@hotmail.com>,<hoss_radbourne@hotmail.com>
    CC: <asa@calvin.edu>
    Subject: RE: Biomass Hydrogen Paper in 29 August Nature
    Date: Wed, 4 Sep 2002 06:15:52 -0700

    Rich Blinne September 03, 2002 4:16 PM

    >What I don't see in the article or the review is any mention of how much
    >energy must be spent to get that hydrogen. The only energy balance they
    >mention is that you get 1 kW per liter volume of the reactor. What is
    >needed before this becomes an energy SOURCE is how much energy is spent per
    >liter volume of the reactor in operating it plus the fixed cost of building
    >the darn thing (steel manufacture, transporation energy, construction
    >energy etc). I can't see that this process would be more efficent than
    >other uses of biomatter. If it takes more energy to manufacture the
    >hydrogen than that which you get out of the process, it is not useful for
    >an energy source.

    Yes, the nasty word endothermic is in the paper. Now there is no
    calculations that I can find to back it up but the paper does say this
    concerning energy balance:

    >Reforming reactions between hydrocarbons and water to generate hydrogen are
    >endothermic, and conventional steam-reforming of petroleum thus depends on
    >the combustion of additional hydrocarbons to provide the heat needed to
    >drive the reforming reaction. In contrast, the energy required for the
    >aqueous-phase reforming of oxygenated hydrocarbons may be produced
    >internally, by allowing a fraction of the oxygenated compound to form
    >alkanes through exothermic reaction pathways. In this respect, the
    >formation of a mixture of hydrogen and alkanes from aqueous-phase
    >reforming of glucose, as accomplished in the present study, is
    >**essentially neutral energetically**, and little additional energy is
    >required to drive the reaction. In fact, the energy contained in these
    >alkanes could be used as a feed to an internal combustion engine or
    >suitable fuel cell; this would allow the use of biomass-derived energy to
    >drive the aqueous-phase reforming of glucose (and biomass more generally)
    >with high yields to renewable energy. [emphasis mine]

    >From what I can glean from both the paper and the review article that while
    prograss has been made but we are not quite there yet, both from a monetary
    and energy balance perspective. Nevertheless, I find the results
    encouraging.

    As for your ethanol example, I lived in Iowa in the '80s. It was pretty
    much an open secret that the ethanol programs was a payoff for the farm vote
    and Archers Daniels Midland.

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