Wood Gasification Prototype Build
Today I would like to announce that I plan on building and testing a high efficiency gasifier similar to Larry Dobson’s wood gasifier PLANS. I plan on providing you with all the manufacturing details and REAL TEST RESULTS! I want to forge the path for all DiYers to build and demonstrate the usefulness of this product.
Probably one of the best reasons is to run a generator for power! Just like in video below
If you do not know what a wood gasifier is or do not understand why you should own one please read my post What is a Wood Gasifier and why you WANT own One!
Once I finish the testing phase, I plan on incorporating an automated control system that will ensure that gasifier always operates at the highest efficiencies possible. This will be accomplished by using properly placed thermocouples to monitor the gasifier’s performance, and to provide feedback to the air damper/agitator’s controller. This will help those who do not want to heat water, but would rather use the exhaust gases to power an internal combustion engine (such as a home generator!). In order to run a generator you want the exhaust gas to be as clean as possible.
Wood Gasification Operation Explained
The picture below shows the main activity zones within the gasifier. The numbers Located in each zone correspond to the numbers in the table below. Read through the chart while looking at the diagram so that you can gain a basic understanding of how the gasifier is setup.
Gasifier Air Flow Path:
1. Air comes into an open bottom duct shell, passing through a rotating damper, then radially outward, where it convects up along the hot inner combustion shell, with the highest air velocity occurring near the shells surface due to natural convection currents (most efficient heat transfer by far). At the top, the heated air transfers outward into the hopper-heating duct, where some heat is removed from the hot air and transferred to the outer surface of the fuel, guaranteeing fuel ignition by the still quite hot gasification air, even when the inner fuel is wet.
2. There is where wood Gasification occurs. This mean that the combustible gases are separated from the wood/ash byproduct.
3. This is where the fuel is added to the Fuel Hopper.
4. This is where the exhaust gases flow through the spiral heat exchanger heating up the water contained on the other side of the inner metal spiral. If your not using the gasifier to heat water then this where the heat contained in the exhaust gases is used to heat up the cold outside air (from zone 1 to 2). This greatly increases the efficiency of the gasifier because must of the heat used to vaporize any water in the fuel is reclaimed. This is why Larry is able to reach such high efficiencies even while burning relatively (up to 50% water) wet fuel!! This is a significant improvement over the imbert gasifier’s design. Although untested, I believe this gasifier will serve to free oneself from reliance on modern society by using a free, renewable energy source.
5. This is where either the producer gas or the combustion exhaust exits the gasifier. If your using the gasifier to heat water in the spiral heat exchanger then at zone 5 you have the exhaust from the internal combustion in the ceramic shell. Realize that which ever mode you use the gasifier in (water heating or fuel gas producing) it always produces fuel gas. Larry has designed the ceramic shell to be a circumferential combustor which helps keep efficiency of the system high. There is actually a controlled fire ring burning around the gasifier during water heating mode!
if you are running a generator you won’t open the second air inlet so no internal fire ring will ever start. The gas exiting at zone 5 is now combustible (burnable!) so you would send this directly into your generator and your up and running!. You could also use this clean burning gas for a stove or any place you would use propane.
Once you understand the function and importance of each zones look at figure 2 which flows the air as travels through the gasifier.
Figure 3 shows the path of the water (which is to be heater) through the spiral heat exchanger. *note you do not need to use this function of the gasifier if it isn’t needed. If you want to use the exhaust gas for another purpose then you would simply close the secondary air damper and drain the water from the heat exchanger.
Please visit Larry’s website to download the complete set of plans and drawings. If you are interested in building one of these for yourself you should look over all of the construction and assembly documents. If you have any questions please feel free to ask.
IF you do not have all of the tools required to take on such a project check back early next week as i announce a smaller project that I plan of beginning immediately! You definitely won’t want to miss out on this one!
I am very excited to get started on this project, but I need to build a few tools First ! more on this next week!
If you want more info on Larry’s wood gasifier see my post on What is a Wood Gasifier and Why you want to OWN ONE!