Peter, No harm done with this question. In most gasifiers it is a trade-off between char yield and gas quantity and quality. Normally the higher the gas quality the lower the char yield. Compare a typical downdraft gasifier making engine quality gas at less than 5% char, more typically about 2%, to a downdraft making 25% or more char and a tarry gas. The engine quality gas needs cooling and dry filtering with a final polishing step for light oils if necessary. The tarry gas needs scrubbing with liquid and filtering before use in an engine. There are costs associated with handling the black soup from a scrubber that are not incurred with dry cleaning. If you have aunique design that makes a high quality gaas an dproduces variable quantiites of char then the choice is which carbon is has the higher net value, so it is a cost/revenue decision rather than just a cost issue.
Tom -----Original Message----- From: Gasification [mailto:[email protected]] On Behalf Of Peter Davies Sent: Tuesday, March 11, 2014 3:31 PM To: [email protected] Subject: Re: [Gasification] Making char vs producer gas David, on a number of occasions you have been personally invited to view our systems here in Australia, including public demonstrations. When you finally do I hope you will stop putting out statements like this below. One of the biggest barriers to commercialisation we have found is the seemingly willful ignorance of consultants and engineers with vested interest in the field who point to statements like this to justify their positions. As Tom Reed will also tell you gas quality can increase with deliberate co-production of char and in our own case is a system design choice that is adjustable depending on project needs. It can in no way be descibed as "De-tuning" the gasifier, it is rather "Optimising for co-products". Planned char outputs can have a number of uses including as a processed fuel, so are not efficiency losses in such a system. Kind regards, Peter On 3/12/2014 8:03 AM, David Coote wrote: > I haven't found any mixed char and producer gas systems in operation > that meet Knoef's commercial criteria which makes me wonder if > detuning the gasification in favour of char does affect the quality of > the gas. -- Peter Davies Director ID Gasifiers Pty Ltd Delegate River, Victoria Australia Ph: 0402 845 295 _______________________________________________ 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/
