Hi Tom,
I'm doing a bit of work in this space at the moment. How did you define
Btu's below for the Btu/kWh efficiency calculation? Was it from the HHV
or LHV of the original biomass fuel?
When you say steam + ORC is that off an existing boiler? The ORC vendors
claim that you can get 20% electrical efficiency at the 2MWe system
level using a biomass system heating thermal oil that would run at much
lower temperatures and pressures than a similar SRC system. Hence
cheaper operations and maintenance costs. I haven't managed to find data
yet on the cost delta between thermal oil biomass systems and the more
common biomass systems heating water/steam.
Regards
David
On 2/02/2013 7:00 AM, [email protected] wrote:
Message: 20
Date: Fri, 1 Feb 2013 09:04:09 -0800
From: "Tom Miles"<[email protected]>
To: "'Discussion of biomass pyrolysis and gasification'"
<[email protected]>, "'stuart mather'"
<[email protected]>
Subject: Re: [Gasification] mycoremediation of tarry water
Message-ID:<[email protected]>
Content-Type: text/plain; charset="us-ascii"
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
_______________________________________________
Gasification mailing list
to Send a Message to the list, use the email address
[email protected]
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org
for more Gasifiers, News and Information see our web site:
http://gasifiers.bioenergylists.org/
