Posted by: etwombly on Apr 05, 2010
Tagged in: news
We have finally reached the point were we are fairly confident we can make no more progress until we make some modifications in the plant to make it work better.
One of the issues, that seems to be a kind of deceptive issue, is the status of char that is not separated from the smoke. It seem while we are running the plant that we are making oil without a problem. It turns out that we are making biooil alright but we are also destroying that which we have made by contaminating it with char. The char soaks up the biooil and eventually fills the cooling tank to such a degree that it can no longer cool the smoke to make biooil. This char soaked oil also tends to plug up the biooil cooling system as well creating quite a mess to clean up.
We have basically gone trough this process in two different ways. First at lower char making temperatures of between 350 and 400 degrees C which yields a grainy char substance in the bottom of the cooling tank that will not flow and plugs up the system which pumps the biooil. Second we also used a higher char making temperature between 420 to 460 degrees C which yields a gooey heavy tar like substance that also sinks to the bottom of the cooling tank but eventually builds up to a point where it can be pumped through the oil cooling system causing a lot of plugging of the venturi system and is not an effective coolant causing problems with the biooil making system.
The reason these are deceptive is that everything seems to be going well the oil seems to be building up in the tank and the good oil floating on top of that that is contaminated with char is working well cooling the smoke into new oil. Unless you are paying close attention the char soaked oil will build up in the tank till it causes problems with out the operator anticipating it.
So we have finally determined that this issue must be resolved before we can run the plant much more in the future.
The problem as it is currently diagnosed is that the current method that is supposed to knock the char out of the smoke is not working effectively. We need to have the plant modified in such a way that the smoke is forced through the cyclone inside the plant at a faster speed than the current fan can draw it through. If this can be accomplished it should take the vast majority of the char out of the smoke before it enters the cooling system to be condensed into biooil. This might be accomplished by installing fan blades in the smoke tube inside the hotbox to move the smoke through this area faster. Of course getting a proper fan blade that can survive in 500+ degrees C may present a problem.
In addition a filter could be included in the smoke stream to get the last of the char out. It would need to be blown off in some way periodically so it would not just plug up.
These modifications along with some improved monitoring and control methods could possibly be included in near future modifications to make the plant work better.
We are discussing how this work could get done and how proper modifications could be made to resolve the above issues in the near future. We have some partners ready to make some of these modifications once proper agreements can be signed.
We hope these can occur pretty quickly, if not we have some other things we may try to make char only since there is lots of demand for char. We don't think this seems like a good idea if we can avoid it since the char only idea really will not get us to our desired goal of a viable production plant that could eventually be built for production use.