[Gasification] Small steam systems plus gasifiers for electricity

Tom Miles tmiles at trmiles.com
Sun Dec 1 13:57:48 CST 2013



We have seen four or five biomass fired Stirling companies fail in the last
15 years. Successful Stirling engine companies  supply the solar and
recreational markets with very small systems and run mostly on LPG.   


Stirling DK had the potential to fill an important niche. I liked their 9
kWe and 35 kWe units. It seems likely that they failed for business reasons
as much as technical reasons. They were very slow to get organized and
capitalize on the early experience of the DTU units. It is not clear why
they charged so much.


We have a few small scale 50 kWe Organic Rankin cycle (ORC) generators in
operation in the US. They seem to work very well for clean waste heat like
exhaust from diesel gensets or biogas. One of my clients is testing one on
diesel exhaust. http://electratherm.com/

The owner of a poultry farm tells me that his ORC unit works fine but the
heat exchanger from his poultry litter fired gasifier keeps plugging up. (We
have been there before.)  He gets 20-30 kWe from the $280,000 machine. The
gasifier and ORC system cost $1 million. There seem to be conflicting
reports about how much the system is actually run. 


Steam systems suit district heat or industrial settings where much more
steam is produced than needed for electricity otherwise load balancing is a
problem. We have seen a 1 MWe wood boiler and steam turbine system fail at a
prison due to the inability to balance heating and electrical loads. We saw
many small turbines in the 250 kWe-1.5 MWe range installed in the wood
industry in the 1970s and 1980s. It was common to see a sawmill generate
higher pressure steam and use a 500 kWe backpressure turbine to reduce the
pressure for distribution to a large number of lumber dry kilns. We have
lost most of our sawmills in our region and electricity is cheap so we
haven’t seen any new systems installed. I visited a 600 kWe Russian turbine
at a district heating plant in Hjordkær, Denmark in about 2004. At the time
they had been running since 1997 and were happy with it. They were serving
about 700 homes and a chocolate factory. It seemed like a good match.  


In recent years we have seen a couple of small scale steam systems in the
250 kWe to 2 MWe range. One supplier will provide a 1 MWe modular fluidized
bed steam system for $5 million. These need to be installed in industrial or
utility setting for reasons cited by others. 


We were disappointed last year not to find more gasifiers with demonstrated
performance in the 2 MWe scale for the Alaska project. Nexterra was just
installing their 2 MWe Jenbacher system at University of British Columbia.
Babcock Volund gave us a budget price but didn’t think putting a unit in
Alaska was interesting to them. Kawasaki Heavy Industries seems to have
abandoned their program that was based on the CarboConsult downdraft
gasifier. Their principal proponent of the system retired. Etc. And we
didn’t want a gasifier with a wet cleaning system. We did receive budget
proposals from some companies that had 150 kWe to 250 kWe gasifiers but that
didn’t have field performance data to demonstrate their production with
multiple units.


We still need to demonstrate more viable small scale systems with any







From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of Thomas Koch
Sent: Sunday, December 01, 2013 9:42 AM
To: Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] Small steam systems plus gasifiers for




Striling.dk just went banckrupt – and gasification gas is Dynamite.




Fra: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] På
vegne af Jeff Davis
Sendt: 1. december 2013 18:37
Til: Discussion of biomass pyrolysis and gasification
Emne: Re: [Gasification] Small steam systems plus gasifiers for electricity


I would have to agree with Steve. Steam is a lot like playing with dynamite.
A gas producer and an off the shelf engine is the system to beat.

Too bad nobody is working on a Stirling engine for using excess heat.


On 12/01/2013 11:29 AM, sabbadess at aol.com wrote:

I found that small steam at the residential scale is just a bad idea.


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