[Gasification] mycoremediation of tarry water

Fri Feb 1 15:50:51 CST 2013

Small turbines and steam engines often have very poor water rates as you
suggest. I know of two systems under development that have much improved
efficiencies. One is a turbine and another an engine. They are at about the
same stage of development as many gasifiers.

I also know of two 50 kWe hot oil driven ORC units whose owners are very
happy with their operation.  They are lucky to have had Mr. Obama buy the
ORC units for them.  

So while gasifiers are an interesting option they are not the only game in
town at the small scale.  

Tom  

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of Kevin
Sent: Friday, February 01, 2013 12:23 PM
To: Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] mycoremediation of tarry water

Dear Tom

Certainly, what you say could be true for 2 MW and larger facilities that
have the technical and economic economies of scale.

Smaller gasifier and engine systems can deliver 1 HP for a heat rate of
about 16,000 BTU/hp-hr. If powering a generator, this is a heat rate of
about 24,000 BTU/kw-hr. I would doubt that small scale steam or ORC plants
could meet this heat rate. 

Small gasification plants can be operated safely with a conscientious
Operator, having very basic training. Steam power plants of any significant
size and pressure, usually Stationary Engineers as Operators. With smaller
steam Plants, the Operating labour Cost can be very significant.

Best wishes,

Kevin.  

----- Original Message ----- 

From: Tom Miles <mailto:tmiles at trmiles.com>  

To: 'Discussion of biomass pyrolysis and gasification'
<mailto:gasification at lists.bioenergylists.org>  ; 'stuart mather'
<mailto:kneebraceboy at yahoo.com.au>  

Sent: Friday, February 01, 2013 1:04 PM

Subject: Re: [Gasification] mycoremediation of tarry water

Except . . apparently when you do a detailed engineering feasibility study
and get quotes from suppliers. In a recent 2 MWe project we found that
gasifiers were 50% higher in capital cost than steam (turbines or engines)
or steam + ORC. In the opinion of a couple of gasifier suppliers, for our
economic circumstances, gasifiers could be more competitive in the 5 to 10
MWe scale. At 10 MWe steam becomes more economic. We were interested to see
that at the 2 MWe scale steam or steam + ORC could be competitive. There are
about 200 ORC systems in operation on biomass but to use ORC you need a use
for large amounts of low quality heat.

We found that while a 5-10 MWe biomass plant may have a heat rate (fuel to
power) of 14,500 Btu/kWh, the efficiency for the 2 MWe plant ranged from
18,500-22,800 Btu/kWh for small scale steam turbines; 28,000-55,000 Btu/kWh
for ORC boiler-turbines and 24,000 Btu/kWh for gasifiers. In this 2 MWe case
gasification did not demonstrate an advantage in capital and operating costs
or fuel to power efficiency compared with steam or steam + ORC.  

Tom     

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of Kevin
Sent: Friday, February 01, 2013 8:01 AM
To: stuart mather; Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] mycoremediation of tarry water

Dear Stuart

Basically, a "Gasifier + IC engine" is cheaper than a "Boiler + Turbine (or
steam engine)".

Turbines must have superheated steam, to enable maximum expansion of the
steam, without having droplet condensation that can be a serious cause of
turbine blade erosion. erosion in a steam engine is not a problem, even with
saturated steam. However, the steam engine efficiency with low pressure
saturated steam is dreadful. Higher pressures and superheat would
considerably improve the efficiency of steam engines. 

Then there is the safety hazard associated with steam. Safety is not a
problem with competent operators, but competent operators are expensive to
hire. Additionally, there are many Government regulations connected to steam
boilers and their operation, because of many fatalities in the past, as a
result of poor boiler design or inadequately qualified Operators.

With woodgas, there are indeed safety hazards, but they are much smaller
than with steam. The main safety hazard with wood gas is the poisonous CO,
but with appropriate  system design and ventilation, this hazard is small.
Additionally, if there is a serious failure with woodgas, it will not be as
dramatic and physically devastating as would be a steam boiler explosion. 

So.... it is worth the bother, especially for smaller installations, to go
with woodgas rather than steam boilers, and to take extra steps to clean it
adequately.

Best wishes,

Kevin

----- Original Message ----- 

From: stuart mather <mailto:kneebraceboy at yahoo.com.au>  

To: stuart mather <mailto:kneebraceboy at yahoo.com.au>  ; Discussion of
biomass pyrolysis and gasification
<mailto:gasification at lists.bioenergylists.org>  

Sent: Thursday, January 31, 2013 11:07 PM

Subject: Re: [Gasification] mycoremediation of tarry water

Ok, steam turbines under 250 hp aren't efficient and a turbine needs super
heated steam. But a reciprocating steam engine is efficient and doesn't need
superheated steam, so aren't these better than trying to deal with tar in an
internal combustion engine?

Stuart.

  _____  

From: stuart mather <kneebraceboy at yahoo.com.au>
To: Discussion of biomass pyrolysis and gasification
<gasification at lists.bioenergylists.org> 
Sent: Friday, 1 February 2013 12:21 PM
Subject: Re: [Gasification] mycoremediation of tarry water

I'm just curious why syngas is ever deliberately burnt in an internal
combustion engine in a deliberate setup when surely it would completely
sidestep the tar/acids corrosion/disposal issue if the heat was just used to
power a steam turbine driven generator? Sorry if it's a daft question.

Stuart.

  _____  

From: Robert Fairchild <solarbobky at yahoo.com>
To: Discussion of biomass pyrolysis and gasification
<gasification at lists.bioenergylists.org> 
Sent: Friday, 1 February 2013 11:40 AM
Subject: Re: [Gasification] mycoremediation of tarry water

This might be a job for mushrooms. Really. Filter the water through straw or
woodchips then innoculate with the appropriate fungus. It's known as
mycoremediation. Paul Stamets is the expert.
See:
http://www.realitysandwich.com/mycoremediation_and_oil_spills
http://www.wsdot.wa.gov/research/reports/fullreports/464.1.pdf
 Bob

--- On Thu, 1/31/13, linvent at aol.com <linvent at aol.com> wrote:

From: linvent at aol.com <linvent at aol.com>
Subject: Re: [Gasification] Gasification Digest, Vol 29, Issue 7: scrubber
water
To: gasification at lists.bioenergylists.org
Date: Thursday, January 31, 2013, 8:15 PM

And some of the gasifiers in India simply dump it in ponds. One very well
funded group set up large tanks ala biodigesters, that didn't work. This is
the same group that spent $200 mm on an Australian  MSW to power gasifier
that was scrapped.  It is not acceptable to dump the produced water in any
normal waste water treatment system. Even in "clean" gasifier gas the
moisture content going to the engine will bring organic acids and other
compounds that will reduce the lifetime and the power output of the engine.
There are effective water treatment systems available, and after years of
trying a variety of options, we have landed on ones that work well and are
relatively inexpensive to construct and operate. If you look at the cost of
a coal gasifier water treatment plant, it is a significant investment.

Sincerely,

Leland T. "Tom" Taylor

Thermogenics Inc. 

-----Original Message-----
From: David Coote <dccoote at mira.net>
To: gasification <gasification at lists.bioenergylists.org>
Sent: Thu, Jan 31, 2013 5:38 pm
Subject: Re: [Gasification] Gasification Digest, Vol 29, Issue 7: scrubber
water

How were they handling the scrubber water, Tom? A colleague visited a 
reasonable size gasifier in Europe where the water was stored in a tank. 
Once this tank was full their immediate option was to install another 
tank. Not ideal!

Waste disposal is becoming increasingly expensive in Australia. This 
would increase the cost of the power.

Regards

David

On 1/02/2013 7:00 AM, gasification-request at lists.bioenergylists.org wrote:
> ------------------------------ Message: 20 Date: Thu, 31 Jan 2013 
> 09:32:11 -0800 From: "Tom Miles" <tmiles at trmiles.com> To: "'Discussion 
> of biomass pyrolysis and gasification'" 
> <gasification at lists.bioenergylists.org> Subject: Re: [Gasification] 
> Power Pallet Message-ID: <00f201cdffd8$e7c8ae80$b75a0b80$@trmiles.com> 
> Content-Type: text/plain; charset="us-ascii"
>> >yes, but remember that all that run these fuels to date are doing so by
>>      
> tolerating a dirty gas non tar solving reactor, and fighting the tar
problem
> in the filtering.  on the low tech end this is nearly always a water
> scrubbing system, which really just>moves the toxic problem somewhere
else,
> and actual real world running is highly unattractive.  yes, it will work
for
> the demo, but the ongoing issues with the bongwater cofferdam challenges
> health, regulatory and general pleasurable>concerns.
> 
> Not so fast. You can't write off "tar making" gasifiers completely. While
> your observation may be true for hundreds of low cost gasifiers now in
use,
> in the last five years I have seen three small scale gas cleaning systems
> using wet scrubbers that would pass California air quality and safety
> regulations. One is produced commercially and was demonstrated at the 300
> kWe scale. Another was demonstrated at 300 KWe and used on a 1 MWe system.
> One was demonstrated on a 100 kWe downdraft gasifier generating 100 kWe
from
> grass seed screenings. I know of another two in development for the 40 kWe
> scale. (I also know of at least one that has failed miserably.)
> 
> Tar making gasifiers may be a solution for some very difficult but
abundant
> fuel like rice husks and agricultural residues if the tars can be managed
> and destroyed acceptably.
> 
> Tom
>    

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