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:[email protected]] On Behalf Of David Coote Sent: Sunday, February 03, 2013 12:42 PM To: [email protected] 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, [email protected] wrote: > Message: 7 > Date: Fri, 1 Feb 2013 15:43:08 -0800 > From: "Tom Miles"<[email protected]> > To: "'Discussion of biomass pyrolysis and gasification'" > <[email protected]> > Subject: Re: [Gasification] Gasification Digest, Vol 30, Issue 1: ORC, > gasifier, SRC systems at around the 2MWe level > Message-ID:<[email protected]> > 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 > > > _______________________________________________ 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.bioenerg ylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/ _______________________________________________ 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/
