chris cromeens wrote:using a rocket stove as the heater core for a wood gasifier. (potential problem: even heating of gasification chamber). Or using a rocket stove as the burner on a distiller (pp: regulating temperature for optimal distillation)
The description of the first idea is still vague. As for the second, a rocket furnace could be used for distillation if a reflux column were used and the column cooled to maintain optimal temps.
There isn't much difference between a rocket furnace and a gasifying furnace if one looks at them fundamentally. A rocket furnace is basically a gasifier that provides excess air through the fuel mass for full combustion. For example, if you pack a rocket "heater" or furnace with smaller pieces of biomass, then it will obstruct air flow to the point where it will smoke. What's happening is that all the oxygen is being used up in combustion and the heat is released in the fuel mass to pyrolyse the biomass. This generates smoke. If the furnace is highly insulated, then it would be possible to route this hot smoke (pyrolysis gas) to a secondary burn chamber where it mixes with air for complete combustion. It would then be called a gasifier furnace. The output would drop a great deal due to the obstructed air flow, and this is why gasifiers often use blower fans. Note: a gasifier designed to generate engine grade gas is more complicated.
chris cromeens wrote:using a rocket stove as the heat source to turn wood into gas in a secondary chamber. Basically a rocket stove that I could set a gasifier on, take the gasifier off, put the distiller on, take it off, etc. sorry for the vagueness
Ok, I see what you mean. So the wood is contained in a vessel (a retort). In principle this could be done. However, whether or not this can be a good idea depends on what you wish to do with the gas generated. It would not be suitable for running an engine. There is a big difference between a gasifier designed for heating applications (such as an updraft or TLUD) and a gasifier designed for generating an engine grade gas (a downdraft or Imbert). It's not merely a matter of geometry, but the systems drive different chemical processes. If you discuss what you're hoping to accomplish, then perhaps we can consider other configurations. Right now the only benefit I see for this configuration is the ability to harvest the heat from a batch charcoaling process where the pyrolysis gases emitted from the retort might be burned for use in heating applications. I discussed this idea elsewhere in a thread called "charcoal gasification" in the Alternative Energy forum.
chris cromeens wrote:I have seen engines run on an updraft system (smaller engines and not efficiently). It is my understanding (I am no expert) that the Imbert system was developed post ww2 and all the trucks and tractors that used wood gasification during the war were updraft systems. I have seen a retort placed in a barrel of burning wood (w/ intake holes at bottom of barrel), w/ a line coming off the retort to a generator, straight to the carb and it ran the generator.
Oh, you can run an engine on pyrolysis gas and it will run strong. Unfortunately, there will be tar deposited in the intake manifold that will eventually sieze the intake valve. Also, the dirty gas will quickly foul the lubricating oil. Running an engine this way will necessitate a regular engine rebuild. An engine is not likely to go more than 10 hours under these conditions without a tear down. One might extend operation by using a solvent between runs to try and strip off the tar "varnish" that will form in the intake manifold and especially near the intake valve, but it sure makes a lot more sense to design the gasifier properly instead.
The Imbert was developed during WW2... by 1943 the Imbert was being mass produced (Imbert is a brand name), but the basic design was developed pre-WW2. All the trucks and tractors that used wood gasification during the war were downdraft systems.
If you want to run an engine reliably more than a few times, then you will have to use a downdraft system. The tar load in the gas from an updraft system is on the order of 1000 times higher than a downdraft. This assumes wood/biomass is used, and not charcoal. An updraft gasifier using charcoal can fuel an engine fine.
chris cromeens wrote:very helpful info, thank you sir
You're welcome, and thank you for asking questions (i.e. doing your research).
I recommend the Handbook of Biomass Downdraft Gasifier Engine Systems as the single best resource on this topic. Also see the lecture series given by Jim Mason at All Power Labs (see YouTube).