A great way to curb the emissions while making something useful.
- Azeem Mohammed
- Presenter’s INNOVATETOMITIGATE
- ne quid nimis
- Jack Ahrens
- Presenter’s INNOVATETOMITIGATE
- ne quid nimis
- Ishan Mundra
- Presenter’s INNOVATETOMITIGATE
- ne quid nimis
- Devin Smedira
- Presenter’s INNOVATETOMITIGATE
- ne quid nimis
Judges’ Queries and Presenter’s Replies
Presentation Discussion
-
-
Thank you!
-
Novel solution with a strong scientific basis. How much carbon dioxide do you anticipate to remove from the atmosphere with this process? How costly would the process be, to build a facility to host the process? Is the reaction dangerous? Are there any by-products of the reaction?
-
Thank you!
Your 1st, 3rd and 4th questions were answered in our paper but it may have been unclear.
We expect there to be a total of about 625 million pounds of CO2, or approximately 24% of the average factories yearly emissions, of carbon captured every year when 500,000 tons of forsterite are used.
As for the second question, it would depend on the particular facility, and we cannot reasonably produce an all-encompassing estimate.
The reaction occurs at high temperatures but is otherwise safe.
Byproducts include carbonate, silica (hydrated or dehydrated) and water (when the silicate isn’t hydrated). -
Further posting is closed as the event has ended.
Nick Ruktanonchai
Postdoctoral research fellow
Nice job, the comprehensive stoichiometry was cool to see and it all sounds quite well-thought out! What would you hypothesize could be the biggest barrier to wide implementation of this idea? Such as (and just a few ideas—curious to hear what you think!), mining forsterite (are mines in particular places?), or the amount of magnesium carbonate created from this vs. the amount used for various applications vs. the amount of forsterite you’d have to keep at power plants?
Azeem Mohammed
Thank you for the compliments and questions!
The biggest barrier to widespread implementation would be, in our opinion, probably just the initial cost. A system similar to one we have described requires a large amount of infrastructure to be effectively implemented, which is both expensive to build and potentially difficult for existing plants to add to what they have. This cost, combined with the cost of operating the reaction, would not quickly be compensated by selling products of the reaction, discouraging businesses from making this investment. To achieve widespread implementation, the factories would probably need some sort of financial incentive to pursue this, probably in the form of federal grants or tax deductions of some kind.
We do not foresee supplies being too much of a concern for implementation in this design. First, there are a wide variety of minerals that could potentially be used in addition to forsterite, which was chosen for its relative success in trials thus far and abundance. This makes the mining and distribution of the one mineral less of a concern. And again, transferring the mineral is not difficult when compared to the massive amounts of coal already transported by the railroads. As for the carbonates, there really would not need to be a concern with them. Even if the market was flooded and prices dropped, a power plant could easily dispose of some carbonate, since it is a stable compound.
Brian Drayton
Co-Director
Very interesting, both the presentation and your answer. I have a couple of additional questions — 1 have you run any tests on a small scale, or do you have ideas for testing the basic processes to understand efficiency under a range of realistic conditions (e.g. imperfect mixing of reagents, different temps, etc.)?
2 I was wondering about net CO2 emissions, including the energy expended to mine the forsterite, etc.?
Ishan Mundra
We appreciate your praise, we put a lot of work into our idea and presentation!
1) Unfortunately, we were unable to conduct experimental testing in the time frame allotted. One problem we faced was related to scale. A substantial amount of carbon dioxide and forsterite would be needed to conduct any meaningful testing which, ironically, causes more pollution. We also lack the mechanism to actually measure carbon dioxide input and output of a certain system, which is critical in measuring the success. Additionally, obtaining the required temperatures in a controlled situation would be very challenging. However, given the necessary measuring equipment, we would probably begin simply by prolonged burning of a sample, measuring the carbon dioxide, and pumping the emissions into the bottom of a simulated smokestack full of the slurry and consequently, measure the carbon dioxide levels emitted from the top. If the experiment was successful and large enough quantities were used, then the carbonate should then be possible to isolate and measure, which would allow the determination of total conversion. That would serve as some sort of general baseline.
2) These are all very significant concerns that you have brought up. However, additional research has revealed that the CO2 emissions involved in processing and transportation are marginal in comparison to the amount that we will mitigate. Operations akin to the one we suggest have not been implemented to the extent where large-scale studies have been conducted. Therefore, to address your question we will suffice to compare it to the transportation of coal. To continue to use our arbitrary 500,000 tons number, slightly over a third of the weight of coal an average plant burns in a year, we can theoretically compare to the effects of coal mining and transportation. Since it takes about 1.4 pounds of forsterite to address the effects of 1 pound of coal, according to our calculations, transportation is slightly more costly. However, oxides make up the majority of Earth’s crust, so the reactive mineral that we would use would ideally not need to travel as far to reach the factory as coal does since coal deposits are only found in certain locations. Therefore, the best that we can answer your question would be to say that the energy to obtain the material would require approximately doubling the energy per pound that it presently costs for coal (that is then cleaned). With some calculations, we also found that approximately 33,000 pounds to 110,000 pounds of CO2 are emitted per kilometer when 500,000 tons of forsterite is transported by train, a small fraction of the amount mitigated. Obviously, more extensive investigation into this question would be important for implementation.
Kate Skog
Research Assistant
Very interesting topic. I have a few questions about the chemistry. Both transfer of CO2 into water and conversion of carbonic acid to carbonate are equilibrium. How do you account for lower solubility of CO2 in water? Since the reaction that makes magnesium requires 4H+, how would that affect the formation of carbonate? How would you address these equilibrium to capture the most CO2?
Devin Smedira
Thank you for the compliments and questions, we apologize for the delay.
To address the problem you present we would implement a water cycling system. If we cycle water, the lower solubility of CO2 in water would not be as significant of a concern since we are not using the same water source to fuel the reaction for too long of a time. By providing a consistent cycle of water, the reaction will be generally be favorable towards the formation of carbonate. Additionally, turbulence actually assists in the dissolution to a minimal extent. The key to make this system effective would be to filter out the carbonates and reuse the remaining chemicals when the water is recycled, resetting equilibrium.
We’re not sure if we completely answered your question and feel free to ask further inquiries.
Sergey Stavisky
Ph.D. Candidate
Great work, Azeem, Jack, Ishan, and Devin. You nicely discuss the motivation for this design, and then provide a thorough technical discussion, including extensions and alternative approaches. You mention that the biggest obstacle is the initial cost, and that this is expensive to install in existing plants. If, instead, this technology were incorporated into new power plants, would this drive the cost down much?
Jack Ahrens
Thank you! Sorry for the long time to respond! We hope you were not looking forward to a one word answer,
To be completely honest, we cannot say to what extent this would drive down cost, as it would likely be a case by case situation. Since the reaction would ideally take place in close proximity to both the boiler and the turbines, we anticipate most existing power plants would struggle with constructing the attachment, and would need to shut down while it is being built. Likely, this would be primarily implemented in new plants, while old ones run would until a new plant is operational. However, in the US, there is definitely a need for a technological update. The average age of an American coal plant is 42 years old, and efficiency has increased to an extent recently. So in a perfect world, many factories would be replaced and implement a design specifically to support our system. In reality, hopefully some sort of incentive system gets put in place to make this happen but in short, yes, we do believe cost would go down in newer plants when compared to those already built.