GEK Wiki / Some ideas to discuss on the forum
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Some ideas to discuss on the forum

Page history last edited by Daniel Chisholm 11 years, 7 months ago

(This is sort of an online bookeeping place; a list of ideas that I'd like to discuss on the forum, and if they prove interesting there, put up a wiki page here.  Anybody else who wants to add stuff here, hop right in!  I'll try not to have more than one active discussion happening on the forum; as I "activate" a discussion over there, I'll update the page to link over to that discussion).


In no particular order, here is a summary of some GEK design issues I'ld like to talk about and thrash over.


  • # of Shells. The existing GEK design uses a double-walled, insulation-filled innermost vessel.  Outside of that is the space where the product gas flows, and contact the air heater tubes.  Then there is a single uninsulated outer shell.  I would like to know why this is done as it is, and whether that's still the right way to go.  For example, could it be better to have a double-walled outer shell, and a single-walled inner one?
  • Managing Preheater Fouling  I think that if some tar deposits on the air preheater tubes, there is no self-clearing mechanism, so various momentary bursts of tar might add up over time to badly inhibit the heat exchanger efficiency.  I muse that we might be able to manage this much better by never drawing possibly-tarry gas through this passage.  Can we monitor the temperature at the hottest area of the reduction zone, and (for example) only permit gas to flow over the air preheaters if is is in the range 700-900C?  All other temps would be considered "fault" conditions (either overheating, or overcooled and tarry); the response would be to close off the flow of gas through the regular path, and draw it out directly from the grate/ashpit area.  I would move the ejector-powered falre suction to get its gas from this area.
  • Reduction Zone diameter and shape  I'd like to discuss the whys and wherefores of straight vs. hourglass vs. conical vs. inverted conical etc. reduction zone designs.  I don't think I have a good understanding of why things are done in various ways here.
  • Sizing and rating the standard GEK.  I think it is worthwhile to establish some reference operating conditions, and quantify what a nominal baseload operation is.  E.g. is the GEK a 50 KWth gasifer on its high fan setting?  Under these conditions, what is the expected air temp at the nozzles?  What are standard system pressure drops across the standard mechanical parts (air heater, cyclone, etc)?  What are normal, and what are abnormal surface temperatures, at this load?
  • "Plug-in" Integrating a Gasifier With Car Engine.  I suggest that for automotive use, a feasible near- to mid-term adoption strategy is a hybrid dual-fuel system (i.e. the engine can be dynamically switched between woodgas and gasoline, or some combination thereof).  Modern car engines use sophisticated computer control but their control computers are proprietary.  How can we effectively integrate an "add-on" alternate fuel source to this?  I would like to discuss leaving the existing engine and its control systems completely unchanged, but physically inserting a gasifier control unit in between the engine computer ("EC") and some of the engine's sensors or actuators.  Specifically, what if we disconnect the EC from the fuel injectors, and have it drive an electrically equivalent fuel injector simulator on the gasifier computer (GC)?  The GC would be able to sense, in real-time, how much gasoline the EC was demanding.  If woodgas is available, the GC can supply a mix of woodgas and gasoline to the engine, by controlling the gasoline injectors and the woodgas admission valve.  If woodgas is not available (e.g. still starting up, or perhaps full throttle has been commanded, and we want to use 100% gasoline for full-power), the GC may pass on the EC's fuel injector commands verbatim.


Comments (2)

jim mason said

at 9:05 am on Apr 24, 2009

this is a very helpful list daniel. thank you. yes, we should work through these and some other main event topics. i apologize for being relatively away from the forum for a couple weeks or so. i've been deep in working out the details of the auger feed unit, tar recycling nozzles, and transitioning to the v3.0 gek. thus less writing for a bit. but please do carry on without me. i'll show up in here again soon.


Bruce Chovnick said

at 7:07 am on Apr 25, 2009

# of Shells... I would think the air tubes could be eliminated with an inner shell that the nozzles could be affixed to... maybe even a simple way to allow thm to be easily reconfigured.

Also, the gas could exit from an outermost shell which would be insulated from the inner shells.

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