RE: GAS-L: Gas "topping" turbines

[Weststeijn A <A.Weststeijn@epz.nl>]

Dear Peter,

Let me try to rephrase your message (Peter Singfield, 1/29/2001) and mine,
refering to gasification coupled to assorted loops of working fluids,
in a more general perspective. Might help to give it a "place" in the
variaty of developments at hand.
 
Assume, there are two principally different extreme's to arrive at equally
economical biomass gasification-to-power conversion scheme's:
*	1) minimizing investment and absorbing the less than ideal fuel
efficiency
*	2) maximizing fuel efficiency and absorbing the associated higher
investment

Case 2) is economy-of-scale sensitive right from the start (high capital
costs to be distributed over a prefereably larger output). 
Case 1) is hardly economy-of-scale sensitive (since low captal costs remain
a quick gain for both large and small sizes and fuel efficiency is based on
a non-scale sensitive unit-of-output basis).

Implicitly, for quick commercial results case 1) is more attractive, whereas
for long term development potential case 2) is more promising.

--------------------------------

So, why would we want to bother with more working fluids than just water, in
the first place? Water being the base case here as the proven state of the
art. The answer lies of course in the usually rather expensive biomass fuel,
upping the complete cycle (fuel+O&M+cap.charges).

Then the question becomes: how can the choise for a working fluids other
than just water make both extreme approaches become more economical. For
this question it principally does not matter whether an independant second
closed loop is added to the common steam-water loop, or whether a mixed
working fluid loop (like ammonia/water) is substituted for the common
steam/water loop.

For both adaptions (adding to or subsituting for the S/W loop) the improved
fuel efficiency needs to make up for the added investment. 

For case 1 (minimum investment, i.e. no added investment) this is a
contradiction. This case, i.e. the low-capital-intensive "step-in" version,
can now be omitted for further consideration with regards to multiple
working fluids. It should be used as-is and not made more complicated and
expensive than the bare minimum. There will be a market for this approach in
its own right, in less technologically developed, or less operationally
skilled, environments.

Remains case 2 (highest efficiency by accepted higher investment) for
further consideration re multi working fluids.
However, that implies that the choise is made for the long term development
option, as opposed to the quick and low-level step-in version.

-------------------------

Case 2 can -by itself- be split in two again:
*	2A) by "semi-coursely" fitting existing equipment as used in other
services (off the shelve), and spending little R&D money
*	2B)  by "finely" developing dedicated equipment, precisely cut to
the job, while spending a larger R&D budget

Case 2B), in my opinion, is open only for the select few of larger R&D
institutions and bigger corporations in the world with substantial financial
stamina. The working environment where max efficiency eventually is written
in two digits behind the decimal point as well.

However, Peter, you are leading us to case 2A) when you point out that one
does not have to be in the top league to apply the same principles for
efficiency improvement, and can afford to sacrifice some of the ultimate
potential (of the multiple working fluids concept), while still ending up
with  a biomass gasification-to-power scheme with a better overall economy
than on Steam/Water only.
But, as stated above, it most likely requires a more advanced technological,
and/or better operationally skilled, work environment.

If you can combine the better economics with the higher level work
environment, then you have it made for sure. The idea is sound enough!

-----------------------

In all fairness, if I try to visualize where these upgraded systems with
multiple working fluids generally could fit well and would pay off for now,
I am led to the well developed area's in the world. 
Are you going to prove otherwise?

best regards,
Andries Weststeijn


> ----------
> Van: 	Peter Singfield[SMTP:snkm@btl.net]
> Antwoord naar: 	gasification@crest.org
> Verzonden: 	maandag 29 januari 2001 15:57
> Aan: 	gasification@crest.org
> Onderwerp: 	RE: GAS-L: Gas "topping" turbines
> 
> At 01:31 PM 1/29/2001 +0100, you wrote:
> >Dear List,
> >
> >With respect to the Kalina cycle and "gas turbines", 
> >
> >I find:
> >
> ****************snipped****************
> 
> >7) no good story yet as how to deal with the (unfriendly) ammonia
> atmosphere
> >in which the full cycle operates. This has severe repercussions from an
> OSHA
> >point of view and will require the full boiler+htex+turbine+condenser
> train
> >to operate under a stringent technical and operational regime. This is
> not
> >to be taken lightly! One reference quotes the working fluid as no less
> than
> >70% ammonia concentration.
> >
> 
> Hi Andries;
> 
> Yes - rather a complicated system to put into operation. A modern high
> quality steam boiler is a "given". "Given" meaning it exists -- is
> produced
> on a regular basis -- is economically feasible and is well "debugged".
> 
> We can certainly say the same of steam turbines designed for high quality
> steam.
> 
> A topping turbine is simply that same device with the last few stages
> omitted.
> 
> Refrigerant turbines are also well developed.
> 
> Duel working fluids systems will bring the same increase in over all
> efficiencies -- probably more so -- are simple to work with.
> 
> The only difference is though the systems exist independent of each other
> -- no one has considered joining both together.
> 
> There is certainly no reason why it would not work. 
> 
> Further -- this style system would be extremely easy to proto-type. Simply
> order the off the shelf components.
> 
> As example -- I took a look at:
> 
> http://www.heuristicengineering.com/
> 
> Heuristic Engineering Inc. Waste-Disposal /Energy recovery systems
> 
> 
> Here we are shown a gasifier that can operate on up to 65% humidity
> biomass
> as fuel.
> 
> I have already researched high quality steam boilers - gas fired. These
> are
> also a "given" -- no problem ordering one up for any size or steam quality
> -- and they are economical compared to other boilers of the same ratings.
> 
> The steam turbine is another "given" -- I know one manufacturer that can
> supply in sizes from 100 kw to 10 megawatt.
> 
> The refrigerant cycle boiler/turbine is also an off the shelf item. Just
> check out the Geothermal power industry.
> 
> To me -- this is a simple process to implement.
> 
> Yet I can not find any references to any such attempt to date.
> 
> For small scale applications -- say 50 kw and less.
> 
> A topping steam piston engine capable on operating with back pressure (I
> have that design) coupled with a refrigerant working fluid steam piston
> engine (I have that design as well)
> 
> I believe 30% over all efficiencies easily -- and possible breaking of 50%
> efficiency level.
> 
> Flow diagram by text:
> 
> Biomass gasifier capable of using high humidity fuels. No complications of
> drying fuel -- or even fuel "conditioning" -- such as pelletizing. Along
> the lines of the first reference in this com -- 
> 
> http://www.heuristicengineering.com/ 
> Heuristic Engineering Inc. Waste-Disposal /Energy recovery systems
> 
> But smaller scale.
> 
> Coupled to a very high steam quality gas fired boiler -- say 600 PSI with
> 1400 F super heat.
> 
> This powering a small steam piston engine which "tops" from 400 PSI 1400 F
> (very superheated) to 250 PSI 400 F saturated steam as exhaust.
> 
> This exhaust steam "condensed" by refrigerant boiler (butane) operating at
> just under 400 F. The exhaust from this would be warm water -- just above
> ambient temperature. Plus waste heat from the butane condenser -- at
> around
> 20 F above ambient.
> 
> We have went over the math modeling. Under these conditions -- very high
> over all efficiencies are possible.
> 
> This is how we can squeeze the most mechanical energy, for the least
> investment, with the greatest reliability -- from heat energy. Small or
> large scale systems.
> 
> A system of 500 to 1 megawatt can be based on turbines as I have a
> manufacturer for both the steam and refrigerant working fluids in that
> size
> range.
> 
> The refrigerant boiler is a standard industrial unit for building
> centralized air conditioning systems -- another off the shelf item. That
> includes the heat exchangers, circulation pumps and the cooling tower.
> 
> Everything exists -- it is simply a matter of connecting them together.
> Some pipe fitting if you will.
> 
> This would be a small, fast, research project of minor investment. I feel
> this would address all the present problems concerned with biomass
> gasification.
> 
> Fuel conditioning, gas cleaning -- would no longer be required. Loss in
> efficiencies in these processes would no longer be occurring.
> 
> Over all efficiencies greatly enhanced.
> 
> And from 500 kw to any size!!
> 
> What more??
> 
> 
> Peter Singfield / Belize
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> >Andries Weststeijn
> >
> >The Gasification List is sponsored by
> >USDOE BioPower Program http://www.eren.doe.gov/biopower/
> >and PRM Energy Systems http://www.prmenergy.com
> >
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> >http://www.nrel.gov/bioam/
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> >http://solstice.crest.org/renewables/biomass-info/gasref.shtml
> >http://www.crest.org/renewables/biomass-info/
> >http://www.crest.org/renewables/biomass-info/carbon.shtml
> >
> The Gasification List is sponsored by
> USDOE BioPower Program http://www.eren.doe.gov/biopower/
> and PRM Energy Systems http://www.prmenergy.com
> 
> Other Sponsors, Archives and Information
> http://www.nrel.gov/bioam/
> http://www.crest.org/renewables/gasification-list-archive
> http://solstice.crest.org/renewables/biomass-info/gasref.shtml
> http://www.crest.org/renewables/biomass-info/
> http://www.crest.org/renewables/biomass-info/carbon.shtml
> 
The Gasification List is sponsored by
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and PRM Energy Systems http://www.prmenergy.com

Other Sponsors, Archives and Information
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