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Producing industrial hydrogen from biomass (charmindustrial.com)
247 points by grantlmiller 36 days ago | hide | past | web | favorite | 102 comments

"Obviously we just needed a steeper cone angle, so we fabricated one at 75° but it still jammed. Perplexed, we increased the angle to 82.5°—practically a straight pipe—and it still jammed. Thus began our surprise introduction to the field of bulk material handling, where entire books have been written and companies have been founded solely to solve this issue known as ‘bridging’, and the frequently-associated ‘hammer rash’."

This is hilarious I think partly because it's such a common theme in engineering or life in general. For some reason things that initially seem so benign and straight-forward end up becoming absolute rabbit-holes of startling complexity.

Looks like they've got some bad Funnel Flow in the hopper. Mass flow is probably the desired flow regime. Using a non-conical hopper is probably a better idea and would negate the vibration, which can fail.

Typically only change the shape of the hopper in one direction at at time as you move down. This often leads to hoppers with an exit that is a slot and not round.

We've used these powder consultants before and I took a week long course on hopper design: http://powdernotes.com

Edit - another method we use to create empty-able hoppers: fluidization. Not sure if this fits with your processing strategy but it also mixes the powder somewhat which prevents size segregation of the particles. And this video is pretty cool:


Could the grass be blown in? Leaf blowers move grass pretty easily...

I would imagine that leaf blowers operate at a much lower density of grass, in an open area where there's nothing for a grass blade to stick on.

First thing I thought about was fluidizing the grass via forced air. Plenty of bulky stuff is handled fluidized. One good example is the hydraulic french fry maker where potatoes are fluidized using water and pushed through a slicing grate using the pressure and velocity of the flow. The water carries the french fries out of the other side just as easily.

You can probably blow it in just fine. The problem is really getting bulk materials out of hoppers. A whole world of research and engineering unto itself.

Start with a simple question like: what kind of model do you use with bulk materials. Obviously it's not a liquid, but as a solid it has tons of weird properties- No tensile strength at all. Strength depends on history of compaction. The list goes on...

My initial thought was vibration, so I was happy to see that was the solution!

I’ve been in bed sick all day with a terrible cold and my sinuses are packed solid.

I had a headache and so out of bordeum tried using my black and decker buffer to massage my head and relieve my headache (I use the buffer as an awesome massager and modded it with a variable speed switch).

To my surprise it worked on the headache and also liquified my sinuses.

A quick google search turned up a few other people playing with vibrators for congestion and at least one patent.

Funny to come across this after experimenting with getting solids to behave at liquids via vibration all day.

Another thing to try is running up and down stairs, while holding a tissue.

Don't give in to temptation and stop too early and blow your nose! Keep going till you have full air flow, only then blow your nose (otherwise the pressure of blowing your nose closes things up again).

After that, consciously keep the nostril on the same side as your headache open, and let the other side close.

The closure is blood vessels in your nose swelling, it's not compacted material. When you exercise your body recognizes the need for more air and reverses the swelling. You don't usually notice, but it's normal to breathe with only one nostril at a time (and the body opens both when there is great demand for air). https://en.wikipedia.org/wiki/Nasal_cycle

Anyway, since there is no actual material compaction, your vibration did not work for the reason you think, rather it acted as a massage for the swollen (irritated) blood vessels.

>I had a headache and so out of bordeum tried using my black and decker buffer to massage my head and relieve my headache

I think the logical next step is to put a boxing glove on a sawzall.

DIY Fucking Machines gone wrong.

I would pay for this in Nerf form, but only if I can use it on my brother.

Grand idea.

Saw this thing in a sappy movie that had a character with cystic fibrosis:


They make it sound fancier than just vibrations though

Since I had a chest cold I also tried it on my lungs thinking it might help loosen things up. Less sure that worked (it felt nice), but I do feel much better today.

I just bought one... What did you use as a variable speed switch? Something like a Lutron Credenza Plug-In Dimmer? I don't know if the buffer is 2 or 3 prong and I'm having trouble finding a 3 prong dimmer that is not remote controlled.

I have the Black & Decker Buffer from Amazon that is about $30. It’s fine on it’s own.

But then I found an old Lutron floor dimmer switch in a drawer and it worked perfectly.

The black and decker is a 2 prong plug.

This is seriously an awesome tool / toy.

I’ve seen other massagers for like $700 that are basically the same thing rebranded.

I just double checked for you.

Black & Decker WP900 Buffer

Lutron Credenza Dimmer TT-300

I was thinking about doing the same the other day but eventually settled for raw garlic instead.

Painful, but effective.

I am intrigued by your ideas and look forward to your product crowdfunding.

It did cross my mind!

I'm skeptical of most bioenergy projects that involve growing things in a field. The best by far I've seen is seen is Brazilian sugarcane to ethanol. Sugarcane is around 8% efficient at converting light into biomass, for comparison corn which the US uses for ethanol is 1-2%. Of course you then have to process those into something else to allow us humans to make use of that energy, so real efficiency is lower.

Compare that to PV solar which is around 18% in a form that humans can use. Of course electricity is more difficult to store than ethanol and hydrogen but there's a big efficiency advantage that has to be made up.

Much better would be to use organic waste. People have to pay to get rid of that stuff so if you can make it your fuel there's money to be made. Hydrothermal gasification or liquification both seem promising for that.

(Co-founder at Charm) Fair points. I'm not going to defend corn ethanol - our process yields 10x more saleable energy per acre than corn ethanol. The energy crop we're currently field trialing is similar to sugarcane, with extremely high yields (and our process uses the entire plant, unlike ethanol). Of course, energy crops are only required at large scale. At small scale, there's plenty of agricultural waste available for cheap, as you mentioned.

PV certainly wins on efficiency compared to crops, but it's also relatively expensive (an acre of PV vs an acre of perennial crops). Also PV is quite unremarkable at removing CO2 from the atmosphere :]

Looks like Miscanthus grass. Although shouldn't it not matter? Why not partner with a corn grower and use corn stalk or chopped corn cobs? Or gasify cardboard.

Also, crops have built-in storage.

Good work! Grasses are the best energy crops, but a serious pain to gasify (or burn, for that matter). Silica plus alkali metals => glass.

You're ignoring the energy and materials costs for building solar panels. Land is not the problem so the difference between 8% and 18% is negligible.

This is a good point, I debated whether to express things as EROI instead of efficiency. Brazilian ethanol is estimated to be about 8:1, corn ethanol is less than 2:1. According to a Wikipedia a 2015 metastudy for solar PV found between 8:1 and 40:1.


So many questions.

How much geological sequestration capacity exists, how long term is the sequestration, and what is the cost of securing it at the necessary scales? Is feedstock local to sequestration formations, and if not, has the transport been factored in?

Why not biogas as a turbine feedstock and sell carbon neutral electricity on the grid (offsetting extracted hydrocarbon)?

What about hydrogen being (my understanding) an indirect plastic byproduct?

What was the drawback of monetizing bio char volatiles while selling the "waste" as a soil amendment products?

I only ask these because I very much want this to succeed and I'm glad to see this here. I get the feeling that the point is very much finding an economic basis for sequestration.

One of the Charm co-founders here. Great questions, and you're correct the point is to find an economically profitable basis for sequestration.

1. In North America alone we have 32,000 gigatons of geological sequestration storage capacity... about 900 years of global carbon dioxide emissions. https://en.wikipedia.org/wiki/Carbon_capture_and_storage

2. We looked at generating electricity, and many others have built and operated biomass-to-electricity plants. The economics don't work out... electricity is very cheap. Most of the biomass-to-electricity plants in California are closing up shop now.

3. Hydrogen may be a byproduct of some plastics manufacturing processes, but not nearly on the scale consumed.

4. Yes, hydrogen is a (cleaned up) biochar volatile! We consume most of the biochar itself as the energy source for heating the gasifier. Any excess biochar will be sold as soil amendment.

Also the USGS has this super cool map of potential CO2 storage in (under) the US: https://co2public.er.usgs.gov/viewer/

"In North America alone we have 32,000 gigatons of geological sequestration storage capacity"

I suspect that is a tendentious estimate, considering no indicative amount of CO2 has yet been geologically sequestered and observed for effects. The wikipedia article has a graphic with CO2 being pumped into a "deep aquifer".

Well, we've had the Sleipner CO2 injection in the North Sea going since 1996 at close to 1 million tons per year, with extremely close monitoring including 4D seismic. There's hundreds of scholarly articles out there with field data and modelling of that case. I think we have some pretty good estimates of how it works by now.

Thankyou, then that is one useful test project. I hold doubts towards what seems to be mostly oil company sponsored research. It is one thing to have estimates for massive geological capacity for CO2 storage, a different thing to claim that capacity exists and that an environmentally sound industry could be developed to fill those, seismically sensed, deep subterranean environments.

Fascinating stuff. If you’re using BECs rather than waste product, have you started to look into how to minimize full-lifecycle energy usage? (Plus water, nitrogen, agricultural crowding-out, etc.) And are you trying to scale up to a centralized production model, or focusing on on-site hydrogen production with logistics from the farms?

What's the flow rate you guys want to achieve and what's the allowable variance?

Flow rate of biomass or hydrogen? Per unit we expect roughly 10-20 tons per day of biomass, and 0.5-1 ton per day of hydrogen. Allowable variance is low, but depends on the customer.

Was referring to the biomass. So at 10-20 tons per day, I'm guessing you go through a hopper worth roughly every 10-15min?

10-20 tons per day is commercial scale. The prototype in this article was much smaller - running around 0.3 t/day.

Thanks for the reply - it's a very cool and clever idea. I can't emphasize how much I hope you succeed.

I get the desire to turn biomass into vehicle fuel. I don't get the desire to involve hydrogen.

Biomass-derived syngas has to be substantially better in energy density and efficiency than any kind of hydrogen.

The leading industrial use for hydrogen is in oil refining, so if you outcompete conventional steam reformed hydrogen on price, you're just going to make gasoline cheaper.

(Charm Co-founder here) Ultimately our goal is large-scale CO2 removal and sequestration with biomass. This process produces an excess of energy which we can sell in various forms to fund the process. We chose to start with Hydrogen simply because it's quite easy and has a large industrial market.

Also note that the largest use of hydrogen (~50%) is actually for ammonia production as fertilizer, which alone is responsible for 1-2% of global CO2e emissions. Decarbonizing that industry would be fantastic.

According to Dept. of Energy:

US annual hydrogen production is approximately 10 million metric tons (1.0E+10 kg), 68% of which is used in petroleum processing.

Given that worldwide production of hydrogen-derived ammonia is 140 million tons in total, compared with hydrotreated gasoline coming in at about 2000 million tons worldwide, it doesn't appear that the U.S. is an outlier.

Decarbonizing the fertilizer industry would be fantastic. Wind-powered and solar-powered electrolyzers are already starting to do that job, perfect uses for intermittent energy sources. I'm skeptical that your process can realistically make more fertilizer than it consumes.

I find it a little disturbing that you boast "Hydrogen's quite easy" with this little public documentation to back up your claims. Be real careful here: you don't want to be the next Theranos.

You have lightning trapped in a bottle because of your luck in landing a YC slot. I encourage you to consider pivoting technologies away from anything involving hydrogen. Since you're such a big fan of ammonia, why not just go straight for that? Getting your nitrogen from the plant instead of from the air might stand a better chance to beat Haber-Bosch.

Charm co-founder here...

(1) electrolysis is much more expensive than steam methane reformation, so unfortunately I don't think it's gaining much steam as a real hydrogen production method.

(2) typical ammonia fertilizer application is 0.125 tons/acre/year at a price of $500/ton = $62.50/acre/year. Our grass and gasification process yields $1,750/acre/year worth of hydrogen... so roughly a 28:1 financial return on the fertilizer input which is probably pretty close to the EROI (Energy Return on Investment)

(3) To clarify "hydrogen is quite easy"... not on an absolute basis (which is quite hard), but relative to other products that could be produced. For example, you mention ammonia, but ammonia production has enormous economies of scale benefits from complex compression systems and pressure chambers... if you run the math it doesn't work out as favorably as hydrogen, and it's substantially more complex and difficult.

(4) We are funded by an amazing group of angel investors, but that does not include YC.

(1) You should check out https://wcroc.cfans.umn.edu/wcroc-news/ammonia-wind (the title specifically mentions "gaining momentum"). (Bear in mind this technology works by making H2 first from electrolysis). There's a half-dozen more of these research groups. Wind and solar electrolysis are sensible because they can be placed next to ammonia consumers that currently have to have ammonia shipped in from thousands of miles away. Unfortunately, your technology is tied to CO2 injection wells, which aren't all that common outside the western US.

(2) I'd love to see your math, but assuming it's not available, let me show you my math: Assume 6000 pounds per acre per year yield of wet grass. Say that's 5000 pounds dried. Model grass as 100% cellulose, which is 6% by weight hydrogen. Assume 100% process efficiency, where you get all the hydrogen out, and it's magically compressed. 300 pounds of hydrogen sounds like a lot, but according to wikipedia, is only worth about 32 cents a pound at the pipe. So my numbers show $100/acre/year. The value goes way up at the "pump", but that's because of transportation infrastructure that neither you nor your competition provide. That also assumes free injection of low-pressure waste CO2, which is not only a fantasy, but presumably ties your process to a location far away from your target market for the H2.

(3) Ammonia solves your hydrogen storage and transmission problem, so my math shows it's way favorable, especially since you're triply tied to a CO2 injection site, fertile acreage to grow your grass, and an H2 consumer. Picking ammonia makes cost-effective transportation to the consumer possible. Realistically, you'd react the ammonia with CO2 to make urea, which is way better than ammonia for both transportation costs and market demand.

(4) Didn't say YC funded you, but you were in their demo day, hence my mention of the YC slot.

(1) When we investigated this last year the ammonia synthesis capex looked untenable and we didn't see a path to lower that capex. Re:injection wells... they are super common in Texas/Louisiana region as well, which happens to be where most of the US refining capacity and ammonia production is located, so we're very near customers there.

(2) 6000 dry lbs/acre/year = 3 dry tons/acre/year which is an extremely low yield. Even miscanthus and switchgrass get over 10 dry tons/acre/year, energy cane gets to 20 dry tons/acre/year and our grass gets to 25+ dry tons/acre/year. So that brings your $100/acre/year up to $800+/acre/year. Then for the chemistry it's important to note that much of the hydrogen gas produced is actually coming from H2O that reacts with carbon in the cellulose to produce 2 H2 + CO2. So, stoichiometrically you get significantly more than the elemental hydrogen content of the grass itself. That gets you another factor of 2 or so... and then we're at the $1750/acre/year mentioned in the parent comment.

(3) Agreed the transportation costs are better for ammonia, but we aren't actually transporting the hydrogen except over a feeder pipe into a refinery or ammonia plant. It's cheaper and simpler to transport the grass as opposed to the hydrogen, mostly because you get to avoid the pre-transport compression energy and losses. Again, as in (1) the issue with ammonia is the heavy capex based around Haber-Bosch pressure vessels and compressors... we didn't have any good ideas for reducing those costs, so there's no sense in competing there.

(4) We weren't at YC's demo day... not sure what you're referring to ¯\_(ツ)_/¯

(1) Since you're limiting yourself to the gulf region, it'd probably be responsible to disclose your CO2 injection costs, including the cost of compressing the CO2 to the necessary pressures. It'd also be responsible to either disavow or embrace enhanced oil recovery vs. other injection approaches: you're either devoted to reducing carbon or making gasoline cheaper, and you have to choose.

(2) If these numbers are accurate, you're doing yourself a disservice by burying them. 25+ dry tons/acre/year is amazing. And I thought the crab grass on my lawn grew fast. I seriously doubt your chemistry, however. Let's look at your three possible approaches (2b sounding the most like what you're claiming to do):

(2a). Charring: Hopefully using all that free low-grade heat from the refinery you colocate with, the cellulose cooks until all the hydrogens join with the ample oxygens in the cellulose and you end up with a char and steam. No hydrogen this way.

(2b). Steam Reforming: This tech works with natural gas because the C:H ratio is so low, and no oxygen is introduced that doesn't bring its own "dates". Because the C=O bond in carbon monoxide is so strong, you can leach off some of the H2. However, as soon as you raise that C:H ratio, or up the available oxygen, steam reforming fails and just becomes combustion. C:H in cellulose is 6:10 vs. methane's 1:4. And that's before the 5 oxygens (vs. methane's 0) ruin it further. No hydrogen this way.

(2c). Fischer-Tropsch (the original Hans and Franz): In a chamber about as expensive as your Haber-Bosch capex, you somehow convert dried grass and catalyst to a mix of H2 and CO, the latter of which you can convert into more H2. Doesn't sound like you're using this approach, though it could technically work if pressure cooking your grass didn't require ridiculous amounts of energy, and you had a way to separate the H2 from the syngas. How many MJ of energy is that? So, maybe Hydrogen this way.

(2d) What'd I miss?

(3) Ok, so your co-founder's protestations about making gasoline cheaper were unnecessary, and you co-locate with oil refineries. Instead of downplaying it, own it: grassoline is trademarked but not for the type of product you'd make. Makes sense to leverage someone else's existing capex, as long as they let you. Those oil guys are flush with cash, why are you distancing yourself from them? They'd love to have your CO2 if it's at high enough pressure.

(4) My mistake. Your timing was highly coincidental with Demo Day, technology looked like it could have been part of it, and the faulty assumption was mine.

Are there hydrogen pipelines that make it easy to sell hydrogen on a larger regional market, or will you have to deal with a ton of transport issues too?

There's this https://www.nextbigfuture.com/2018/11/nanomembrane-based-tec...

Don't mean to rain on the parade, but I am skeptical

That advance is for combining hydrogen and nitrogen in order to make ammonia. This company is talking about production of hydrogen, so the technologies complement one another.

Indeed, but they're also touting that the energy component of haber-bosch can come from complete combustion of the charcoal, which is where some (much?) of the economic incentive comes from to pay for 'geologic sequestration'.

If a less energy-intensive ammonia process is used, perhaps a simpler hydrogen-generating process would be a better fit. ie, if the heat can't be used directly, is this process an economically viable way to generate hydrogen?

Their goal as a company isn't energy density or efficiency, it's atmospheric CO2 reduction. Their production of hydrogen displaces CO2 production by other methods, uses plant mass which is sequestering CO2 from the atmosphere, and produces hydrogen fuel that can be burned or consumed in fuel cell vehicles with zero CO2 emissions. Even if it gets sold to an oil refinery in the short term, it'll have offset and sequestered CO2 compared to their previous source of hydrogen. That means the lifecycle CO2 emissions of the cars running off the resulting gasoline will be lower.

Consider the Pepsi challenge between a straight natural gas wellhead and using lawn. The natural gas tap requires no natural-gas derived fertilizer, no grid-derived irrigation, no fuel-based harvest or processing, and doesn't deplete soil of nutrients. It doesn't remove CO2 from the air but it likewise doesn't add CO2 to the air from its use of the aforementioned.

Steam reforming the natural gas and then injecting the CO2 can't be any harder than charring the grass clippings and then injecting the CO2.

At least corn-derived ethanol is a decent motor fuel, for all its limp efficiency numbers and carbon-positive growth cycle. If you're willing to overlook the warts of this hydrogen technology, I don't see why you're not instead advocating for corn-based ethanol.

And if making green industrial hydrogen is your goal, PV-powered electrolyzers can outperform this in process efficiency, complexity, scalability, and deployment cost, all without consuming fertilizer, (as much) water, or depleting soil.

This article is about getting chopped up grass to flow through a hopper (so that it can be gasified for fuel).

If you want to read it don't get stuck at the top (the start makes it seem like the article is about gasification instead), keep going till the images start.

Side note: From read this article they desperately need some experts. They are re-solving solved problems, and not working on what their startup is actually about. (I should add that them seem to be aware of this.)

> Side note: From read this article they desperately need some experts. They are re-solving solved problems, and not working on what their startup is actually about. (I should add that them seem to be aware of this.)

That was my thought as well. These guys may have a viable business idea, but they don't appear to have any engineering experience at all, nor do they appear to understand that one can research for existing solutions, or hire/consult with experts. It doesn't bode well for the entire enterprise.

Looks like they forgot to proof read their website too.

"If you are want to consume carbon-neutral hydrogen, please reach us at sales@charmindustrial.com"

I wish them the best of luck, but I've seen the first wave of biofuels fail and pivot to selling cosmetics or go under (Amyris, Solazyme, LS9). Sure, this is different, but the economics haven't really changed. It's damn hard to compete against something you can pump out of the ground and has no price tag on its externalities.

Personally, I think more effort put into lobbying and activism is better spent. I know we have the technology to make carbon-neutral fuels. I sincerely hope that we transition to using something like EVs for all ground-based transport and biofuels for applications like jet travel that need the energy density.

However, it's the market and the economics that don't work out. And they don't work in a way that prevents you from having easy stepping stones to scaling up. There's basically no-one who will buy this commodity at small scale for a much higher price. You have to succeed completely or fail.

You can even look at startups using conventional approaches and cheap feedstock (Siluria with methane). 10 years and still working on their tech. These big commodity markets have huge players who have huge competitive advantages.

Hydrogen is a mistake anyways, they should make syngas instead. https://en.m.wikipedia.org/wiki/Syngas and then Substitute natural gas (SNG) https://en.m.wikipedia.org/wiki/Substitute_natural_gas

And if you check the articles people already make those. I guess their "new thing" is using grass? switchgrass is usually considered the best plant for this.

I don't really understand why they are reinventing things that already exist.

Charm co-founder here... thanks for the typo find, fixed!

People have been lobbying and protesting for years, I don't believe it's going to fix things on its own. Policy makers need legitimate technology options to put support behind, and that's what we intend to develop.

Thankfully you are simply incorrect that "no-one who will buy this commodity at small scale for a much higher price". We are in active sales conversations with a number of buyers who are very much willing to pay a premium for the commodity given its reduced carbon intensity.

Charm co-founder here... Two quick notes:

(1) we agree wholeheartedly on the experts front — for the core technology around gasification we've been working with a variety of PhDs, national labs and companies with extensive previous gasification experience,

(2) the gasification technology we're developing is actually fairly novel and unfortunately in this industry that means patenting is in our future, which means that we're not going to blog about the core parts of our gasification system... instead we can blog about the surrounding systems that still represent interesting challenges. So that's why we blogged about grass flow. Rest assured 95% of our time is going into gasification ;)

In case anyone is curious as to how bio-gassification compares to electrolysis (or a hybrid process), I found this 2009 paper [1] that sums it up decently (at least with the technology available at the time):

(Note: SEK := Swedish Krone; currently ~$0.11USD and was roughly the same in 2009)

Abstract: "An integrated system for the production of hydrogen by gasification of biomass and electrolysis of water has been designed and cost estimated. The electrolyser provides part of the hydrogen product as well as the oxygen required for the oxygen blown gasifier. The production cost was estimated to 39 SEK/kg H2 at an annual production rate of 15 000 ton, assuming 10% interest rate and an economic lifetime of 15 years. Employing gasification only to produce the same amount of hydrogen, leads to a cost figure of 37 SEK/kg H2, and for an electrolyser only a production cost of 41 SEK/kg H2. The distribution of capital and operating cost is quite different for the three options and a sensitivity analyses was performed for all of these. However, the lowest cost hydrogen produced with either method is at least twice as expensive as hydrogen from natural gas steam reforming."

In addition to a dollar-to-dollar comparison, however, I think a Carbon-to-Carnon byproduct comparison is also warranted. If you don't have to pay for geo-sequestration (or the messy supply of grass compared to piped in water), is the small cost increase of electrolysis over bio-gas more than compensated for?

As an H2 advocate myself (as an industrial transportation battery alternative), actively looking to boost H2 fuel supply infrastructure, I would be interested to hear from Chimere (OP co-founder) on this point. I ask, because I don't know the answer.

1.) https://www.sciencedirect.com/science/article/pii/S036031990...

Interesting question - I'm not sure I know the answer but happy to speculate. Electrolysis certainly is a much tidier process than gasification, but everyone seems to assume it's powered by 100% renewable energy. What incentives exist to make H2 production decarbonize faster than the rest of the electricity grid? I'd expect electrolysis to only be fully carbon-neutral when the rest of the grid is, which will take some time.

On the other hand, our process is close to carbon neutral from day one (we've confirmed this with an external life cycle assessment), and will become significantly carbon negative when we begin sequestration. And as I mentioned elsewhere, sequestration is the primary mission and electrolysis is unremarkable at it :]

Thanks for the response!

So, my point is that in the bio-gas process, you are generation H2 + CO2 and using some proceeds from H2 sales to sequester the CO2 you produce.

However, with electrolysis (from renewable elect. plants), you aren't generating any CO2, so any profit that you spend on Carbon sequestration (from somebody else's process) would be a much more Carbon negative proposition overall.

All this depends on the H2 production cost as to which is a mor effective Carbon sequestration scheme, right?

In the paper I cite (I convert SEK to $): bio-gas costs ~$4/kg H2 (let's say this produces 5 kg of CO2), and electrolysis ~$4.50/kg H2 (producing 0 kg Carbon).

Now say it costs $0.50/kg for CO2 sequestration). In the biogas process, because of the cost to sequester the CO2 byproduct, your actually spending ($0.5×$5)+$4 = $6.50/kg H2 produced just to get Carbon Neutral. However, for electrolysis (without the mess) you're only spending $4 to be Carbon Neutral, and if you want you can spend $2.50 (which you avoided by chosing elect. over gas), to go Carbon negative.

These are rough numbers I guessed at based on a little googling. Am I far off on the real numbers?

I'm really not trying to be a pain. What you're proposing is still light years better than the greedy bastards reforming natural gas and pocketing 100% of the profits without giving a second thought to the environment. I'm just wondering if there might be a way for you guys to do even more good, more easily.

The economics you're looking at for biogas and electrolysis look roughly right to me. But our models suggest that thermal gasification of biomass can get down to $1/kg. So then you're looking at $4.50+/kg for electrolysis or $1/kg for gasification... and you can see how all that math changes.

Electrolysis also typically costs more than you'd expect as soon as you add the requirement of renewable energy supply. Usually the renewable energy supply is solar, which has a ~30% duty cycle. So 70% of the time your electrolyzer is sitting idle. This crushes your economics and makes solar-powered electrolysis untenable in all of the analyses I've seen. We didn't have any clever ideas for how to change that situation, so after looking at it ~1.5 years ago we decided to look elsewhere.

Good answer, thank you. Like I said, it all boils down to the cost of H2 production for a given process. If you have a path to get to $1/kg H2, that is truly awesome!

Working very peripherally in this sector, I applaud your efforts, not only for the ingenuity, but also for the guts to consider environmental impact as opposed to stock-holder happiness from a profit margins perspective.

Honestly, it would be cool if on your site you showed a side-by-side comparison on your profit model compared to a competing natural gas reforming competitor's profit structure to demonstrate to customers how you are sacrificing some profit for environmental benefit, whereas the competition simply pockets the profit and turns a blind eye to the environment. For me, that would help me decide to buy potentially higher cost H2 from you, just like I choose to pay a higher premium for energy I know is renewable sourced.

The world needs more innovators like you folks. Good luck!

I remember seeing a video demoing how to make sand flow like water by bubbling air into it: https://youtube.com/watch?v=My4RA5I0FKs

(Charm co-founder here) I love that video! That fluidization phenomenon is commonly used in large-scale gasification or combustion processes, see: https://en.wikipedia.org/wiki/Fluidized_bed_reactor

You probably know, but don't forget that compressing air is energy intensive. I'm not saying that the extra expense can't be marginalized - especially if you can dramatically increase production, I'm just pointing out that it's far from free. Just another fun engineering problem to tackle:)

That was my first thought too.

I was just talking with a coworker about how we could theoretically modify our espresso machine hopper to avoid blockages. This is a great survey of bulk material handling options.

How advanced is the hydrogen production prototype?

Looking at the Wikipedia page https://en.wikipedia.org/wiki/Steam_reforming this looks like a difficult process, even when using methane that is a very small molecule and is easy to purify. Big molecules in grass are more eager to produce soot that would block the machine, and grass also has other elements like Nitrogen and Phosphorus that may react with the catalyzer, and there is the ash problem.

Is using a grass more efficient that burning the grass and use the energy to produce Hydrogen with the standard method?

What about producing ethanol from the grass and then using the ethanol to make the Hydrogen? (Both parts are somewhat proven technology.) And ethanol is easy to move and purify than grass.

"With the addition of geological carbon dioxide sequestration it becomes carbon-negative."

LOL, easy peasy then

Can you make "grass charcoal"? If so, just pile the grass high and cover in a layer of clay before burning, as is done with wood. Then bury the charcoal, which also improves the soil

(Charm Co-founder here) Certainly - you're effectively describing biochar (https://en.wikipedia.org/wiki/Biochar) which historically has been used as both an energy source and a soil amendment. Using it as a sequestration method has gained some attention recently, though I have reservations.

For one, biochar is typically produced in small, low-efficiency reactors without proper emissions control (though this is solvable). The bigger issue is the high energy content of biochar (~30MJ/kg). Simply burying all of this energy isn't economical - it makes much more sense to store carbon in its oxidized state, and sell the energy that's released in the process (in various forms - we're starting with Hydrogen).

Thanks for the reply, yes I am aware of biochar but wasn't sure grass was a suitable source.

The latest research seems to show that done properly, biochar can improve crop yields substantially, so that could be a way to pay for the process, but the other aspect is that it can be produced in a very low-tech manner, which is almost certainly the situation in many or most parts of the world.

How are you planning 'geological carbon dioxide sequestration'? I'm not sure of the chemistry/process, but is burning the charcoal completely actually necessary to produce hydrogen? It seems not, to me. The cynical view of course is that you will omit the costly sequestration step, which makes this just another biofuel endeavor, with the attendant pros, and, mainly (IMHO), cons...

Did you try blowing air through the mass from bottom up? It can help loosen the grass chips, reduce moisture and prevent agglomeration and is useful as long as the air flux doesn't prevent the grass from funneling down.

Certainly we considered it. The problem is that on this prototype system we were operating with a sealed hopper. Thus any gas injected into the hopper would travel through the system and dilute our output gas stream. Also any oxygen in the injected gas would result in combustion rather than gasification.

The inside of the funnel can be lined with a tube punchered uniformly and use pneumatic nitrogen piped from above and outside of the sealed hopper? I’m getting these weird ideas in my head.


If you want to have the grass flow like water, could you take a stream of water and add grass to it? The water could carry it down a wide pipe for example, you filter the grass from the water at the destination, then send the water back to get more grass?

Things start happening to grass when you put it in water. That might be OK depending on your other processing steps. A similar idea is pneumatic transport, where you add material to an air stream and then use a cyclone to separate the air and the grass.

Looks like the issue is the feed stock, non-uniform particle size distribution and significant differences in aspect ratio. All the different pieces are clumping up because of the particle interlocking. Maybe consider a grill sorter on the outlet of your size reduction system, allow <1cm particles through and rehandle larger particles back into whatever is chopping, or add secondary size reduction.

Where is the evidence that carbon sequestration works?

Stanford Prof. Sally Benson's talk here is a great overview: https://youtu.be/lIVwbSnD0AI?t=127

Specifically, she talks about the results of the Sleipner Project in the North Sea, where they've measured leakage rates, etc: https://youtu.be/lIVwbSnD0AI?t=1199

Still seems like this is a big guess that sequestration works over long periods, or at all at the scale necessary to be industrially significant. I’m inherently sceptical of anything hydrogen related due to the fuel’s association with delay tactics from the carbon industry. Chevron would prefer we all not buy electric cars in hopes of HFC becoming a real thing which, obviously, is just a farce to keep paying them to produce, transport, and sell solid fuel. I think we are better off as a society not burning carbon at all, not looking for places to put carbon polution.

Charm co-founder here... We are not betting on hydrogen fuel cell cars. There is an existing $120B/year market for hydrogen used in the production of ammonia fertilizer and oil refining. That hydrogen is currently produced from fossil natural gas, and we are replacing that.

The Sleipner Project for geological carbon sequestration has been ongoing for 20 years with extremely rigorous measurement. We also know that natural gas is stored in geological deposits for millions of years, and in vast quantities. I don't see a strong reason to be skeptical of long-term sequestration a slightly different gas in those same geological formations.

Natural gas wasn’t injected down there by man. I can tell you’re sincere but those are not the same things. This still seems like a giant guess. We’re better off burning as little carbon as possible.

Couldn't they use a manure spreader to throw the grass onto a conveyor belt at a steady rate? Manure spreaders come with variable flow rate and beaters to shred the manure. If you threw a bale of hay in there it would tear it up and throw it nicely.

Here is an example:


Is there a reason you need to make it flow as opposed to simply conveying it mechanically? It seems like you came up with a complicated solution (making solids behave like liquids) when there are plenty of simpler solids handling techniques that could be used. For example a belt or screw conveyor.

I like this. Slightly related, I am planning on building a house eventually and I really want to incorporate a domestic biogas generator for cooking. Something like https://www.homebiogas.com/

Can the ash be used as a concrete additive?


Charm co-founder here... possibly, but it's likely more valuable being sold as potash.

you want to mix the grass with air so you have grass suspended in a flow of air just like a fluid. since you need to avoid oxygen blow this grass nitrogen suspension through some pipes and into your gassifier.

'Charm’s mission is to return the atmosphere to 280 ppm CO2 profitably'.

i.e., 2,130,000,000 metric tons of CO2 (= 1ppm) * (410ppm - 280ppm) or some 276 giga tons. Evidently a modest goal.

I would have loved to be there the moment they first tried a funnel and failed. Bulk material handling seems pretty interesting to solve.

I wonder what dampening the grass might do, as this might reduce the volume of the grass (increase density).

First guess is it'd make it mat together worse by adding surface tension into the mix.

I feel like this might make the grass harder to vibrate into a "fluid".

what % of the generated H2 is currently consumed by the sequestration?

If no other energy source is available, does this % change?

So how does the sequestration work?

wouldn't it be easier to pelletize the grass before feeding it?

why not blow the grass?

> Naively, we assumed that grass would flow somewhat like an ideal fluid,

Perfect sustenance for spherical cows.

> allowing us to use a simple, funnel-like hopper.

But, since that one didn't vibrate, it could hardly be called a grasshopper.

>Perfect sustenance for spherical cows.

Engineering students discover that real world specialized solutions are in fact optimized for what they do. Water is wet. More breaking news at 11.

This is one of my favorite comments so far this year.

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