Well, I am still working on getting the gremlins out of my project and I will continue to update that thread if I have any progress, but in the meantime I thought I would start a new thread if anyone wants to tackle one or both of these two questions. In an attempt to understand gasification much better I have been spending a lot of time reading up in the DOW library, and I came across a couple of questions that I wanted to ask - the first one will probably be pretty simple the second one might need a little more explanation - so here goes….
Question 1. Relates to charcoal in the gasification process. Prior to coming to DOW I did not even know that there was such a thing as charcoal gasification, but now with this new knowledge that seems so popular with many my question is this:
So gasification requires 4 processes Drying, Pyrolysis, Combustion and Reduction - however that is based on wood gasification if I am correct - so if this is the case, which of these processes does charcoal gasification skip or bypass? I am thinking obviously it has skipped the drying process, and it would seem that it would also have to go through combustion and reduction - but I am wondering is pyrolysis already completed when charcoal is made? Anyway, any of you charcoal guys that want to chime in , I would really like to understand charcoal better as it relates to the 4 processes and if it “skipping” a couple of steps or bypassing part of the process that wood would normally have to go through.
Question 2. This one might be a little more complex - I am trying to learn the relationship with oxygen better. So far I have learned that smoke passing over hot coal strips the oxygen molecules off CO2 and H2O leaving behind CO and H2. I have also learned that this makes a clear gas that you see above the head of a match before it combines with oxygen and turns into a flame. So far so good, I understand the relationship prior to making syngas and the process required to make that reaction happen. So the question I guess I have is the relationship of oxygen post syngas production - since it seems like we are stripping away something that we will again use or need again later. Does the oxygen in the environment create the combustion? I would not think this is the case or else flare gas would spontaneously combust - so then is it ambient air plus heat that equals combustion which I guess would be the conditions of a match head?
I am trying to learn more about the process by which smoke passes through the coals, gets converted into usable syngas and then eventually combusts and turns back to smoke.
Here is how I am currently understanding it - the basic match head example, there is the match, the clear syngas, then combined with oxygen near the hot match head becomes flame, and then smoke is produced. Specifically I am trying to learn this process better so that I will be able to better understand and troubleshoot my project.
My understanding so far is that a gasifier, when it is first started, produces only smoke for a few minutes - because the coal bed is not hot enough. But then presuming the coal bed is hot enough, how would an air leak also produce smoke? Does it combust inside the gasifier and come out as smoke? Sorry if this second question sounds stupid, I am just trying to understand the process much better so that I can figure out which gremlin to continue to chase in my project - to go down the trail of “my hearth isn’t getting hot enough” or to keep chasing down the trail of “I must have an undetected air leak”. My thinking is if I can understand the process better, perhaps I can isolate down to just one cause to start looking into instead of chasing down multiple things that could be giving me problems.
For anyone unfamiliar with my project it is on another thread with pictures of it and my progress, that thread is called “New gasifier project giving me troubles”