RE: GAS-L: Wasted heat retrieval to electrical power

[Peter Singfield <snkm@btl.net>]

Hi Andries

At 10:33 AM 2/19/2001 +0100, you wrote:
>Hi Peter,
>Peter, a temperature difference of 18 degrees C doesn't say much in itself
>(we remove hundreds of MegaWatts-thermal at low temperatur with only 7
>degrees C difference).

*********snipped***********

>One tends to keep delta T's up to keep investment and operating costs down,
>but that is no particular accomplishment in itself.

Yes -- exactly the reason I "push" it up to 400 or 450F -- with a delta of
310 to 350F.

I still have to circulate over 4.5 times more working fluid than in a
conventional steam design -- but for small systems -- this is not a hard
price to pay. Especially when one looks at all the other costs saved -- and
the resulting over all efficiency increases.

Let me put you people straight on why over all efficiencies are so crucial
in designing/building.

It takes the same "tonnage" of boiler to make a 5% or a 30% over all
efficiency plant.

I have some quotes, from last year -- for a state of the art bagasse
cogeneration plant for the Orange Walk sugar factory. Electrical production
of 16 megawatts. Cost of $2640 per kwh -- or total cost of 42.240 million
(US) dollars.

This a fire tube boiler of 450 PSI and 850 F steam.

I seriously "doubt" their claim of 16% over all efficiencies. So to keep
the playing field level -- I will claim (in my opinion -- a lower
expectation) 32% efficiency -- or double the present "estimate".

So lets start retrofitting.

I need a complete butane power plant for 32 megawatts power production.
Steam from the "planned" fire tube boiler powering the butane evaporators.

Part of this price will be absorbed by the greatly reduced condenser
required -- which is a large part of the original plan cost. As I am now
extracting more heat into power -- much less condenser capacity is required.

Plus -- we will not need the steam turbine -- which is another great part
of the costs.

So -- if we plan on the same price per kwh -- I have 42.24 million "extra"
to implement the butane cycle -- plus a lot of spare change coming back
(probably 10 million) from eliminating the steam turbine and extra large
condenser -- costs.

Right??

>
>About Japan:
>could it be that the cost of thermal energy for distric heating and cooling
>is relatively high in Japan, so as to allow for more costly waste heat
>systems to be installed?

Even if it is not -- they are planning for the future shortage of fossil
fuels -- where Western "Civilization" is still in a dream land. You know --
"It can't happen here" -- along with "Da*n the torpedoes -- full speed ahead!"

Again -- we should cut this topic -- it is not relevant to Western energy
production philosophies. And this list is only interested in that.

Anyone on this list even in a position to approach a geothermal power plant
maker for quote on a system optimized for 450 F operation -- of 32
megawatts capacity??

Minus the well driving -- the pumps -- etc. Just bare bones -- with two
fittings for hot water in and cooled water out.

Then Andries -- you would have your answer -- I have 42.240 million and
change to pay for a 32 megawatt -- bare bones -- geothermal power plant.

Peter

>
>best regards,
>Andries
>
>