> Light and flexible pieces of wheat straw in San Francisco had easily been conveyed pneumatically from the tub grinder into the hammer mill.<p>Okay, that is a very basic failure of engineering/imagination. I’m not saying shame is in order here, but several someone’s should be made to feel uncomfortable over this cock-up. Including the hiring manager because they went for kids instead of people with experience.<p>Why on earth would you assume you could move corn residues with air? Have you seen a corn field before? Have you touched corn? This is the other problem of moving engineering far away from the problem. SF only sees so many refugees from Iowa and Illinois. Most of those go to Chicago or Seattle.<p>> But with some deeper searching, we found a great, off-the-shelf belt that would arrive quickly.<p>Arrive quickly because the locals have been solving this exact problem for a hundred years. When you find an off the shelf solution for your problem, that’s when a good engineer or software developer takes umbrage and considers whether they have a bad, bad case of NIH.
For quite a few years I looked into similar processes based fundamentally on biological photosynthesis, for example algal pool farms and similar approaches to generating hydrocarbons from biomass.<p>At present, I think direct air capture of CO2 followed by reduction to methane and longer hydrocarbons using water-sourced H2 (all without going through the biological photosynthesis) is going to be the long-term winning technology. One main reason is control of the chemistry is a lot easier when you start with uniform small molecules (CO2 and H2) rather than trying to distill off and separate the products of pyrolysis of biomaterials (or even of crude fossil oil distillation and cracking, a similar process).<p>This isn't to say that if you have a completely renewable energy based power system, that converting agricultural byproducts to useful materials like biomethane, biooil and fertilizer (phosphorous recovery in particular) isn't going to be a plausible approach in specific situations, and the resulting products could have niche markets.<p>Now, if your goal is to remove CO2 permanently from the atmosphere, that's more difficult. Making materials like limestone (CaCO3) or perhaps carbon fiber is a better idea for that. Bricks of diamond would be even better, but that's a bit more sci-fi still - but possible. Air-captured diamonds would be a cool product.
So the ELI5 is they burn crop waste, harvest the heat and bury the carbon-rich ash. This process is called BECCS. (Not totally right - see 'pkrein’s comment below.)<p>The upper bound on capture is pretty good! Almost 70% of yearly CO2 emissions.<p>> Intergovernmental Panel on Climate Change (IPCC), suggests a potential range of negative emissions from BECCS of 0 to 22 gigatonnes per year
[1]<p>> Human activities emit over 30 billion tons of CO2 (9 billion tons of fossil carbon) per year
[2]<p>1 - <a href="https://en.m.wikipedia.org/wiki/Bioenergy_with_carbon_capture_and_storage" rel="nofollow">https://en.m.wikipedia.org/wiki/Bioenergy_with_carbon_captur...</a><p>2 - <a href="https://en.m.wikipedia.org/wiki/Carbon_dioxide" rel="nofollow">https://en.m.wikipedia.org/wiki/Carbon_dioxide</a>
I’m having a tough time understanding how this makes sense.<p>Is this even close to being financially viable if there is never any such thing as carbon credits?<p>Put another way, are the people funding projects like this assuming there will be some kind of carbon credit system in place that will pay absurdly high prices to sequester carbon?<p>Additionally, I suppose you will be compensating farmers for their corn stalk bales, but you can’t take something OUT of a field long term without replacing. Those bales contain more than just carbon and the farmers will eventually have to amend the soil to compensate.<p>Which, if we are then living in your sky-high carbon credit world, fertilizer (and everything else) pry got MUCH more expensive.
In their FAQ, they mention this statistic.<p>> Every ton of biomass contains roughly 1.65 tons CO₂.<p>On it's surface this is impossible. Does this refer to CO₂ equivalents like Methane? It seems that for carbon specifically, the process (pyrolysis, transportation, etc) emits more than one ton of carbon for every ton of oil sequestered.
If you or your friends are mechanical engineers, we're looking for great meche's with experience in thermal, fluids, combustion, ag processing and more. Would love to chat: <a href="https://charmindustrial.com/team" rel="nofollow">https://charmindustrial.com/team</a> or email in my profile.
Interesting fact about those whole truck dumping systems:<p>There is a small vent that you have to open at the front of the trailer BEFORE you raise it to dump out the contents.<p>Failure to do so leads to a vacuum effect that can implode the trailer as the biomass pours out<p>Source: friend of mine worked in the paper industry and this was a somewhat regular occurence
> solid material handling in general, is a perennial problem<p>Ugh! Yes. One one machine I worked on, this was one of our major issues. We had a subsystem whose job it was to get small plastic containers out of a bulk hopper, orient them correctly, and deposit them into a carriage all with a failure rate, IIRC, on the order of "no more than one unrecoverable jam every 10,000 units."<p>An "unrecoverable jam" was one that required human intervention to open the container and clear the jam by hand. Fun fact: tiny nonconductive plastic containers are very susceptible to static cling!<p>This was my introduction to bulk material handling (I was the dev writing the code) and its associated patent minefield. Just about every good idea the very experienced mechanical engineer could think of was already patented. In the end we got it to work and met the spec, but not without a lot of hard work.<p>At my previous job we had similar issues with paper. The company had an entire Paper Handling lab staffed with people constantly working on better ways of moving a sheet of paper from one place to another at speed. Paper might actually be worse because changing the humidity changes its properties quite a bit.
The title "Corn Cobs: Fuel of Nightmares" reminds me of this bit of pop culture where Rick and Morty land on a corn cob planet:<p><a href="https://www.youtube.com/watch?v=aw-2KuHIYyo" rel="nofollow">https://www.youtube.com/watch?v=aw-2KuHIYyo</a>
Pkrein, I see you posting here. I've got 200 acres of forest in Washington State and I'm long term interested in providing biomass for carbon sequestration, what can I be doing now to connect with companies like yours to help ensure those 200 acres are as carbon negative as possible?
I like seeing the modern engineering write up here. Almost everytime I read green energy/ag stuff, it’s either math latex or marketing copy. I assume it’s because IP protection but problems/solution/problem is the kind of stuff that becomes good conversations
This is some kind of<p><a href="https://en.wikipedia.org/wiki/Bioenergy_with_carbon_capture_and_storage" rel="nofollow">https://en.wikipedia.org/wiki/Bioenergy_with_carbon_capture_...</a><p>?
Interesting post.<p>Is there a "mechanical engineering for dummies" educational path (Book? Software? Kit?) that would equip someone for doing like 90% of the mechanical design&prototyping work?<p>Interesting point: "when you solve one bottleneck you find a new one somewhere else."
Honestly, all I am hearing is whining.<p>There are so many ways to transport material up. Miners transport ROCKS, upwards, from kilometers beneath Earth surface. They then crush those rocks into fine powder to extract tiny specks of gold from it. Magic? I don't think so.<p>So you chose a wrong tool for the job and are blaming corn?<p>You moved from a lab to "real world" and are surprised it is not all nice, uniform and spherical?<p>I love history of ASML. These guys faced a problem after a problem after a problem for like a decade just to get one process that everybody thought is impossible. Didn't give up. Didn't complain. Just focus on solving it.
I love this story. The lesson here is that the real world is messy and good engineers have to think on their feet. It also gives me hope that somehow humanity will actually solve climate change.
This may not be generally practical, but just to get a prototype working I'm surprised they didn't employ gravity. The vacuum wasn't strong enough to lift the cob debris up 5-10' to the top of the hammer mill, but it certainly could have pulled it out of the bottom of an elevated tub grinder and down to a lower hammer mill.
I wonder if just buying crude oil and burying it isn't more cost effective than transporting bulky biomass which could have been fed to animals in order to put it through this complicated process of converting it to oil and burying it.
This is such a great article, the summary of which is “I/O is hard”, which every programmer surely knows (and if they don’t, they haven’t tried).<p>Ok, it’s a great article for other reasons too.
How do you get so far into a project before you even realize that you have such a show-stopper problem? Move fast / fail fast works with software because iteration times are quick and penalty per iteration is low. But just building stuff and hoping it works and then realizing major problems doesn't work so well with real-world stuff. Couldn't they have "workshopped" this with non-functional item to see what the real world roadblocks would have been before a deep investment?<p>This is especially the case in high-risk unproven areas such as cleantech where the solution space is vast and potential problem areas significant. Any problem area can kill a project, so why are we progressing so fast to build first?