Re: GAS-L: RE: Torrefied-densified biomass

[Reedtb2@cs.com]

Dear Andries et al:

Thanks for the coal perspective.  

During WW II cheap coal carried the energy load for large installations.

More expensive biomass carried the load for small gasifiers, home heat etc.  

It is not unlikely that this mix will continue where the convenience of 
biomass fuels and pellets, briquettes justifies cost at a small scale, but 
coal always can win in plants designed for it.  

I came across the (Indian?) saying "The present foreshadows the future" the 
other day.  How about, "The past and present guide the future"?

TOM REED                            BEF/CPC

In a message dated 1/11/01 1:01:50 PM Mountain Standard Time, 
A.Weststeijn@epz.nl writes:


> Hello Gavin,
>
> > Gavin Gulliver-Goodall wrote on woensdag 10 januari 2001: 
> > There is a great deal of waste heat around the Coal power stations here in
> > the UK (30% efficiency only!)
> > I guess the problem is that the Biomass is too far away!
> > 
> A bit of numerical perspective "from the field":
>
> 1. We won't like comparing the potential of biomass gasification on the
> basis of WW2 gasifier vintage. Equally we won't like comparing the potential
> of biomass cofiring on the basis of outdated coal plants.
>
> 2. A 15 year old pulverized coal plant -built back then as state-of-the-art
> plant- typically has an efficiency of 40%. That is 1/3 better than Gavin
> quotes.
> A 5 year old coal plant typically has an efficiency of 43%.
> A recent coal plant (like in Denmark) goes to 45%.
> The big european design study presently running (with british utilities and
> boiler+turbine companies involved) aimes at 50% for around 2010.
>
> We operate a 7 year old 600 MWe coal plant in heat-and-power service (yes,
> only gasturbines plants usually get credit for that, but coal plants can do
> just as well) at better than 50% efficiency overall.
>
> 3. Biomass is too valuable a commodity to NOT convert in the most efficient
> way.
> Biomass does not come cheap either. Whether the price is being paid for
> growing, ag waste collection, or additional plant modifications etc, it is
> sure not a free ride.
> But in reasonably up to date plants a fair amount of energy can be extracted
> even nowadays.
>
> 4. Personally, I prefer to look ahead a few years to where bulk biomass
> cofiring may play an increasingly large roll. The averige plants with
> sufficient life time expectancy left at that point in time, will sure be
> running at 40% efficiency or better. In heat-and-power service (district
> heating, greenhouses etc) at 50% or better.
>
> Hope this gives some perspective.
> Coal is black, indeed, but coal plants can handle friable solid fuels well
> with little modification. That is just what they are designed for.
> So how to make that biomass friable, economically, that's the 100$ question.
> Torrefaction+densification may provide part of the answer.
>
> Best regards,
> Andries Weststeijn