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Launch HN: Heimdal (YC S21) – Carbon neutral cement

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Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#181

Post by marcuslima »

froh wrote: post #105
marcuslima wrote: post #53

Earlier quoted context omitted.

Yep, exactly! The world needs CaO for cement. We have a carbon neutral process for making it. It's actually overall negative as not all carbonates we extract are usable in cement production. But as far as cement producers are concerned it's carbon neutral.

so there is no more additional burning of limestone needed? instead your process directly produces the lime, CaO? and that then binds the CO2 when curing? to my limited understanding cement production emits CO2 in two ways: by splitting limestone into lime and co2 and by burning carbon based fuels to split the limestone. your method addresses both sources of co2 from cement production? or just one of them?

Our process produces calcium carbonate, CaCO3, which cement producers can then burn to make quicklime, CaO. This does release CO2 but that CO2 has been captured from the atmosphere in the process of making that calcium carbonate. We only address process emissions (ie. splitting CO2 from CaCO3), but we do also produce hydrogen on-site, which can be used to replace fossil fuels in generating the requisite heat

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#182

Post by bbyford »

wow, long and interesting thread! I'm sure people have already pointed out but your website needs a content overhale to actually say what your doing and roughly how... also, tangent question, can concrete be made from concrete? just thinking what happens when we cover the earth in the stuff we could use something else or reuse?

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#183

Post by marcuslima »

galgalesh wrote: post #143

Could it be profitable to take advantage of the overabundance of renewable energy during certain periods of the day? Or does profitability require running the process 24/7? I'm thinking, for example, whether this could sink some of the overabundance of solar energy in places like California.

Absolutely! This is a big part of our thinking for how this integrates with future energy systems based on renewables. We'd offtake cheap electricity when oversupplied, like in California right now

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#184

Post by immmmmm »

(former) cement scientist here.

you say we are "addicted" to cement/concrete which is correct, but then propose more cement? i get we might need cement here and there for energy transition and might need your tech. but isn't using less cement a better/complementary approach?

im addicted to tobacco, not sure natural tobacco is my best bet.

at a time where half of the world is burning, do we need more 10 ways bridges for huge cars?

how do you tackle the worldwide sand shortage problem?

does your tech solves the issue that comminution (grinding) of clinker is one of the biggest electricity consumers worldwide?

how does that scales up, how long to deploy? what are the consequences (please be honest) to marine life, knowing that most kelp forests/corals are now gone/bleached?

how does your tech tackles the massive corruption problems that come with concrete?

thanks in advance

edit: don't take it badly, your tech looks promising on paper.

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#185

Post by ephbit »

marcuslima wrote: post #72
LeifCarrotson wrote: post #66

Earlier quoted context omitted.

I understand that calcium salts and bicarbonate ions are common in the ocean, and are increasingly common as the oceans become more acidic, but have no idea how common that is. How much seawater do you need to get one kg of CaCO3 precipitate?

We're actually working on figuring this out. Our current calculations assume we need to process a huge amount of seawater (11,000 tonnes per tonne of CO2), if the CO2 is the limiting factor (2000 umol). However our R&D suggests undersaturated seawater re-absorbs CO2 from the air surprisingly quickly. Might be able to get this 10x lower

Wow .. 11,000 tonnes of seawater per tonne of CO2 is indeed huge.

Assuming that the new process stochiometrically generates CaO according to the amount of CO2 taken up from the ocean you'd produce 1.27 tonnes of CaO per tonne of CO2. (molar masses of CO2 and CaO: 44 g/Mol and 56 g/Mol)

Cementa website states [1] an annual output of 2.7 million tonnes of cement.

So in order to produce what is only a portion of Sweden's (a comparatively small country) annual demand for cement, Heimdal's process would require processing of ~ 23 billion tonnes of seawater.

That's 23 billion cubic metres or 23 cubic kilometres per year or ~ 730 litres of seawater per second.

[1]: https://www.cementa.se/en/about-cementa

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#186

Post by quickthrower2 »

immmmmm wrote: post #184

(former) cement scientist here. you say we are "addicted" to cement/concrete which is correct, but then propose more cement? i get we might need cement here and there for energy transition and might need your tech. but isn't using less cement a better/complementary approach? im addicted to tobacco, not sure natural tobacco is my best bet. at a time where half of the world is burning, do we need more 10 ways bridges f…

One startup cannot solve all the problems right?

Also I like solutions that don't rely on people changing their habits, because they are most likely to work.

The alternative to tobacco is no cigars or cigarettes, the alternative to cement is not simply no buildings, no railways, no roads, no infrastructure.

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#187

Post by radicalbyte »

marcuslima wrote: post #177
hedora wrote: post #145

Earlier quoted context omitted.

What sort of waste water do you produce? What is the local ecosystem impact? Edit: Also, it’s great that your de-carbonating the ocean as part of this project. Ecological damage to the ocean is out of sight, and usually out of mind.

All 'waste' we produce we either consume in our process or we're able to sell as a commercial product! Not bad tackling ocean acidifcation to boot

I was just about to make this point: as I understood it, ocean acidification is a massive environmental problem.

Would your process reduce the local acidification significantly? Could there actually be a win-win situation here deploying around coral reefs? Especially given that such reefs are found in countries with massive solar potential (i.e Australia).

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#188

Post by marcuslima »

brilee wrote: post #157

I did some lengthy analysis behind the chemistry / economics and wrote it up here. https://www.moderndescartes.com/essays/carbon_neutral_concre... TL;DR: ignoring all sources of overhead/inefficiency and purely on consideration of thermodynamic costs, $70 of electricity can generate $100 of lime, $300 of chlorine gas, and $75 of hydrogen gas. Much more details on the chemistry and economics in the blog post...

Impressive analysis! Missed out on a couple details, but I'll take that as a thoroughly researched/analyzed endorsement. Most importantly, we'll be scaling up a lot faster. Our current 1t/yr is just a demo. Our current roadmap is scaling up to a 300t/yr pilot in the next few months before setting up building a commercial plant (10kt+) in the second half of next year. Any chance we can poach you from Google? ;)

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#189

Post by marcuslima »

dang wrote: post #164
brilee wrote: post #157

I did some lengthy analysis behind the chemistry / economics and wrote it up here. https://www.moderndescartes.com/essays/carbon_neutral_concre... TL;DR: ignoring all sources of overhead/inefficiency and purely on consideration of thermodynamic costs, $70 of electricity can generate $100 of lime, $300 of chlorine gas, and $75 of hydrogen gas. Much more details on the chemistry and economics in the blog post...

Wow, that's the most in-depth response to a Launch HN I've ever seen. This is probably the most substantive Launch HN thread (I mean of the official YC startup launches at https://news.ycombinator.com/launches ) that we've yet seen. And it was very little work to put together.

Agreed!

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#190

Post by marcuslima »

go_elmo wrote: post #174
brilee wrote: post #157

I did some lengthy analysis behind the chemistry / economics and wrote it up here. https://www.moderndescartes.com/essays/carbon_neutral_concre... TL;DR: ignoring all sources of overhead/inefficiency and purely on consideration of thermodynamic costs, $70 of electricity can generate $100 of lime, $300 of chlorine gas, and $75 of hydrogen gas. Much more details on the chemistry and economics in the blog post...

Thanks for the analysis, interesting to read! What about the lime-burning for cement, does it imply "only" net-carbon neutral as all the captured carbon is released upon cement production? And what about iron smeltering? I suppose most carbon is also released in that process?

Same idea for iron!
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