Launch HN: Heimdal (YC S21) – Carbon neutral cement • Hacker News Board

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

#221

Post by liketochill » Thu, Aug 05, 2021, 4:48 AM UTC

ephbit wrote: post #185

marcuslima wrote: post #72

Earlier quoted context omitted.

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'…

.73 m^3/s of seawater is only a pipe of 1m diameter with water traveling at 1 m/s. Not that big a pipe in the grand scheme of things!

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

#222

Post by liketochill » Thu, Aug 05, 2021, 4:52 AM UTC

marcuslima wrote: post #29

filleokus wrote: post #27

Really cool! Looking forward to follow your journey. I understand that you might not be ready to share numbers, but you mention both hydrogen and desalinated water as byproducts, which both are quite energy intensive to produce. Any chance to give a hint along the lines of: X kWh of power + sea water + sorbent (consumable?) => Y% CaCO3 + Z% H2 + W% H2O When at scale, will your synthetic limestone be much more expensi…

Our synthetic limestone will be on par with mined limestone. At scale when accounting for the higher calcium content per tonne and value of carbon we expect to be cheaper even than mined limestone. You hit the nail on the head there. The most important cost factor is energy. We're looking at <3MWh/tonne of CO2 removed. Somewhat higher than some competing DAC companies that claim 1.5-2.5MWh. But these guys have the ad…

Is it that expensive to pump the c02 back down an old oil or gas well so that it is stored underground again?

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

#223

Post by [deleted] » Sun, Aug 08, 2021, 11:37 PM UTC

marcuslima wrote: post #25

Angostura wrote: post #23

I wish you the very best of luck. The kind of company that I'd like to be involved with and I'mm sure the same goes for others here. Just one thing. https://www.heimdalccu.com/our-story linked from your front page gives 'Page Not found'

Thanks a lot! Stay posted for open roles - we'll be needing to add to our team in the next few months. Thanks for pointing out - will sort this out!

[deleted]

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

#224

Post by Angostura » Sun, Aug 08, 2021, 11:41 PM UTC

Interesting, the entire website - other than a content free holding page has now disappeared,

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

#225

Post by rsanek » Tue, Aug 10, 2021, 2:37 AM UTC

Take a look at Stripe Climate if you're looking for customers -- https://go.stripe.global/climate-projects

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

#226

Post by pankajdoharey » Tue, Aug 10, 2021, 7:55 PM UTC

galacticdessert wrote: post #172

pankajdoharey wrote: post #162

Earlier quoted context omitted.

It seems what they do is Ocean Water + Sorbent -> Leaches Carbonates for use in Cement -> Heated in Kiln -> Releases C02 -> Captured and redissolved in Ocean water. This still has to be proved how to reabsorb such large amounts of c02 in ocean water.

Absorbing large amounts of CO2 happens every second since 2-3 centuries at this point, and is the main driver of ocean acidification and subsequent coral bleaching, loss of wildlife, etc. If the mentioned process could "recycle" the CO2 needed for lime production, then it could be a big win for a very hard to decarbonize sector. What is still to be checked is how more expensive this lime will be, and how it will stac…

Price can be justified, if the government puts carbon tax on cement companies who dump large quantities of CO2 in the atmosphere.

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

#227

Post by ephbit » Wed, Aug 11, 2021, 5:23 PM UTC

liketochill wrote: post #221

ephbit wrote: post #185

Earlier quoted context omitted.

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'…

.73 m^3/s of seawater is only a pipe of 1m diameter with water traveling at 1 m/s. Not that big a pipe in the grand scheme of things!

True. Not that big.

But let's not forget that it's not about merely pumping the water around. All this water must be processed. And I figure the process is a little more involved than simple reverse osmosis for seawater desalination.

In the desalination business 1 m diameter pipes with water traveling at 1 m/s and the resulting volumetric flow rate isn't a big thing .. but I'd guess for more complex processes it indicates huge/expensive apparatuses.