[Gasification] ORC, gasifier, SRC systems at around the 2MWe level

[Tom Miles]

David,

The advantages that Turboden cites for low pressure, manpower, etc. probably
work very well where you are fitting ORC into an existing wood plant. Their
recent 2 MWe installation in British Columbia at an existing wood plant with
a hot oil boiler and a large demand for low quality waste heat is a perfect
fit. If you are thinking of a small scale stand-alone plant then the picture
changes. Other cost factors offset the proposed benefits.

Our wood products industry hasn't been completely sold on hot oil. One
company took out their hot oil system for dry kilns and went back to steam.
Some are concerned about the hazards of an oil spill in a remote location.
When asked about oil spills PW/Turboden told me that of course you would
have to have a "mitigation plan." It wasn't clear what that was or what it
would cost. 

My take is that ORC works well where you have cheap fuel or more waste heat
than you can use, you have a favorable power purchase agreement, and you can
afford a $15-$20 million plant (ORC part is about $8 millioon) to generate 2
MWe and a lot of heat.

Tom   
  

-----Original Message-----
From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of David Coote
Sent: Sunday, February 03, 2013 12:42 PM
To: gasification at lists.bioenergylists.org
Subject: Re: [Gasification] ORC, gasifier, SRC systems at around the 2MWe
level

Hi Tom,

Turboden et al claim that the lower temperatures and pressures in an ORC 
system compared to an SRC system of similar size lead to reduced 
maintenance costs and - as a guy with a specialist high-pressure steam 
ticket is no longer required - also lower operations costs. I was 
wondering what you have come across which leads you to say below:

"The manpower and capital requirements are pretty similar for both the steam
and ORC systems because of safety and other considerations."


What are the varied experiences with hot oil you mention? There have 
been some spectacular fires at thermal oil plants - there's a cracker of 
a YouTube video showing one from memory somewhere in the US NE - but the 
industry says that the newer oils are much less flammable

Thanks

David

On 3/02/2013 7:00 AM, gasification-request at lists.bioenergylists.org wrote:
> Message: 7
> Date: Fri, 1 Feb 2013 15:43:08 -0800
> From: "Tom Miles"<tmiles at trmiles.com>
> To: "'Discussion of biomass pyrolysis and gasification'"
> 	<gasification at lists.bioenergylists.org>
> Subject: Re: [Gasification] Gasification Digest, Vol 30, Issue 1: ORC,
> 	gasifier, SRC systems at around the 2MWe level
> Message-ID:<00f901ce00d5$e3b9ed10$ab2dc730$@trmiles.com>
> Content-Type: text/plain;	charset="us-ascii"
>
> David,
>
> Heat rates were calculated the American way, using HHV.:-)
>
> Steam and ORC was proposed in different configurations. A couple of
> companies proposed using backpressure turbines or steam engines with oil
> heated from the exhaust to drive an ORC turbine. Other proposed hot oil
> boilers and ORC turbines. The 20% efficiency of Turboden and others is 20%
> of the heat input to the turbine so you have to subtract the efficiency of
> converting the wet wood fuel to hot oil which runs from 62-72% of HHV
> depending on the MC of the fuel and the boiler configuration. Now since
you
> have 70% of the heat input exiting the ORD as waste heat you need to dump
it
> to a heat consumer. That work fine if you have an onsite heat consumer or
> district heat arrangement. Unfortunately most of our American towns are
not
> laid out so conveniently that we can afford to build a district heat
system
> for a small biomass plant.
>
> I agree that for all the literature on ORC there are very few head to head
> comparisons with steam of CAPEX and OPEX. The manpower and capital
> requirements are pretty similar for both the steam and ORC systems because
> of safety and other considerations. In the end the levelized cost of
> electricity (LCOE) will be higher for the ORC if you don't have a heat
> customer. If your need is primarily heat , or if you have waste heat
> available, the ORC systems look great. A new 2 MWe plant on Vancouver
island
> with a PW/Turboden ORC uses oil from an existing hot oil boiler at a wood
> plant. There are many more hot oil systems in use in Canada than in the
US.
> We have had varied experience with hot oil here.
>
> Tom
>
>
>    


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