Posted by: etwombly on Jan 08, 2010
Tagged in: news
It has been an interesting few days since my last entry. We basically have the plant and dryer running but we are having a steep learning curve at this point.
Since we resolved the wire brush in the venturi and we have had good luck running the plant. An interesting problem has occurred. That is that we are now producing so much syngas we are having trouble overheating the plant.
The first time we ran the plant after fixing the ventrui brush we got it so hot we had to shut it down in a short period. We had in the process gotten the dryer too hot and we were burning the surface of the chips while being dried.
We discussed this problem with ABRI and decided we needed to be able to divert some of the syngas to the pyrolysis reactor. We made the modification and with two large valves and two inch pipes we can now send gas to either the reactor or the dryer.
We though this would be the solution to the problem. In fact we have discovered we are producing enough syngas that we can run the reactor and divert excess to the dryer. In fact we have so much that we control the temperature of the reactor and send the rest to the dryer and the dryer can still over heat. This overheating of the dryer happened with the first test after the new diversion was installed to the reactor.
Surprisingly this excess amount of seems to be caused by modifications ABRI made to this plant before we picked it up in Ottawa. It was mostly by increasing insulation that there is very little heat loss. These modifications seem to have made the plant so efficient that it produces all its needed heat once started. But it can easily get our of control and over heat. We are experiencing that problem now.
The over heating started a chain flail which is part of the dryer unit to start banging on the side of the housing for these flails. The flails break up the chips and bounce them around in hot air till they are dry. This caused us to think one of these flails had broken a weld or something. We dismantled that part of the unit to find it was not really a serious problem but ground down the edge a bit so it would not continue to bang.
We then fired up the reactor and dryer again. Things were going well for a while but for some reason the electric motors on the flails stopped a couple of times unexpectedly and by the time we got them started with all the syngas we are producing it caused the dryer to over heat. So we had to shut it all down again.
Interestingly at this point we are able to run both the reactor and the dryer with only syngas after initial start up. If we are not careful we will over heat the dryer as stated above. It seems to go along fine till we have some kind of problem and in each case the dryer becomes overheated and we have to shut the system down.
We discussed this problem Friday night and have some possible procedures to work around this issue we plan to test in the next week.